LR - Syllogisms - Previous Year CAT/MBA Questions
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1. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. All software companies employ knowledge workers.
B. Tara Tech employs knowledge workers.
C. Tara Tech is a software company.
D. Some software companies employ knowledge workers.
E. Tara Tech employs only knowledge workers.
- (a)
ABC
- (b)
ACB
- (c)
CDB
- (d)
ACE
Answer: Option
B
Text Explanation :
ACB is the correct answer choice. as it forms a valid syllogism.
CEKW = Companies that employ knowledge workers SC = Software companies
TT = Tara Tech
The premises state that all software companies employ knowledge workers and Tara Tech is a
software company. Therefore, Tara Tech employs knowledge workers.
(a) ABC is invalid, because if Tara Tech employs knowledge workers, it cannot definitely be concluded that it is a software company.
(c) CDB is invalid, because if only some software companies employ knowledge workers, Tara Tech may not be among them.
(d) ACE introduces a fourth term. ‘Companies that employ only knowledge workers’ and, therefore, violates the very definition of a syllogism, which must have 3 and only 3 terms.
2. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. Traffic congestion increases carbon monoxide in the environment.
B. Increase in carbon monoxide is hazardous to health.
C. Traffic congestion is hazardous to health.
D. Some traffic congestion does not cause increased carbon monoxide.
E. Some traffic congestion is not hazardous to health.
- (a)
CBA
- (b)
BDE
- (c)
CDE
- (d)
BAC
Answer: Option
D
Text Explanation :
(d) BAC is the correct answer choice, as it forms a valid syllogism.
TC = Instances of traffic congestion
ICM = Instances of increase in carbon monoxide in the environment.
HH = Instances that are hazardous to health.
The premises state that increase in carbon monoxide is hazardous to health and traffic congestion increases carbon monoxide in the environment. Therefore, traffic congestion is hazardous to health.
(a) CBA is invalid, because if TC and ICM are both separately hazardous to health (HH), no definite relationship between TC and ICM necessarily follows.
(b) BDE is invalid, because the some TC that are not ICM need not necessarily be free of any hazard to health (HH): they could possibly pollute the environment with other noxious gases.
The shaded portion shows those some TC that are not ICM, but could possibly be hazardous to health (HH).
(c) CDE is invalid, because the conclusion E is a negation of one of the premises C. Another check reveals the TC is the middle term, which appears in both the premises C and D, and E, therefore, should not appear in the conclusion E, as per the basic definition of a syllogism.
3. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. Apples are not sweets.
B. Some apples are sweet.
C. All sweets are tasty.
D. Some apples are not tasty.
E. No apple is tasty.
- (a)
CEA
- (b)
BDC
- (c)
CBD
- (d)
EAC
Answer: Option
A
Text Explanation :
(a) CEA is the correct answer choice, as it forms a valid syllogism.
Figures
S = Sweets
TT = Tasty things
A = Apples
Sweets are a subset of tasty things. Apples are not tasty things. As apples are not a part of the main set of tasty things, they can also not be a part of the subset of sweets.
(b) BDC is invalid, because the set of some A that are S and the set of some A that are not TT may have no relationship with each other (disjoint sets).
(c) CBD is invalid, because some A that are S are definitely TT, but we have no knowledge of the remaining A, and hence can reach no conclusion about them.
(d) EAC is invalid, because if all A are neither S nor TT, we cannot establish a definite relationship between S and TT.
4. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. Some towns in India are polluted.
B. All polluted towns should be destroyed.
C. Town Meghana should be destroyed.
D. Town Meghana is polluted.
E. Some towns in India should be destroyed.
- (a)
BDE
- (b)
BAE
- (c)
ADE
- (d)
CDB
Answer: Option
B
Text Explanation :
(b) BAE is the correct answer choice, as it forms a valid syllogism.
PT = Polluted towns
SBD = Things that should be destroyed
IT = Indian towns or towns in India.
The shaded portion are those IT which are polluted (PT) and hence should be destroyed (SBD).
The premises state that polluted towns should be destroyed and that some towns in India are polluted.
The ‘some’ in statement E refers to the polluted Indian towns that should be destroyed.
(a) BDE is invalid, because with B and D as premises, the only valid conclusion that follows is C. Town Meghana should be destroyed. ‘Town Meghana’ cannot be simply replaced by ‘Some town in India,’ as in E.
(c) ADE is invalid, because the syllogism has more than 3 terms. The term SBD does not appear in the premises A and D, but appears in the conclusion E as a new and fourth term.
(d) CDB is invalid, because we can’t talk of all PT in the conclusion B, when we only have information about Town Meghana in both the premises C and D. In deductive reasoning, we cannot proceed from specific cases to general cases. It would, however, be valid to conclude that ‘some polluted towns should be destroyed.’
5. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. No patriot is a criminal.
B. Bundledas is not a criminal.
C. Bundledas is a patriot.
D. Bogusdas is not a patriot.
E. Bogusdas is a criminal.
- (a)
ACB
- (b)
ABC
- (c)
ADE
- (d)
ABE
Answer: Option
A
Text Explanation :
(a) ACB is the correct answer choice, as it forms a valid syllogism.
P = Patriots
C = Criminals
B = Bundledas
Since patriot and criminal are two distinct sets, what
is patriot, cannot be criminal. Therefore, if Bundeldas
is a patriot, Bundeldas cannot be a criminal.
(b) ABC is invalid, because if no P is C and B is not C,
we cannot be definite that B is not P.
Bundledas (B) may be a patriot (P) or not. Nothing definite can be concluded.
(c) ADE is invalid, on similar lines as explained in the case of (b).
(d) ABE is invalid, because the syllogism has four terms: patriots, criminals, Bundledas and Bogusdas.
6. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. Anteaters like ants.
B. Boys are anteaters.
C. Balaram is an anteater.
D. Balaram likes ants.
E. Balaram may eat ants.
- (a)
DCA
- (b)
ADC
- (c)
ABE
- (d)
ACD
Answer: Option
D
Text Explanation :
(d) ACD is the correct answer choice, as it forms a valid syllogism.
Bl = Balaram
AE = Anteaters
LA = Creatures who like ants
Anteaters like ants and Balram is an anteater.
Therefore, Balram likes ants.
(a) DCA is invalid. Just because Balaram likes ants and he is also an anteater, it does not logically follow
that all anteaters like ants. It would, however, be valid to conclude that ‘some anteaters like ants.’
(b) ADC is invalid, because if Balaram like ants, we cannot definitely conclude that Balaram is an anteater,
as evident from the Venn diagram.
(c) ABC is invalid, because it has four terms:
Anteaters, creatures who like ants, boys and Balaram.
Furthermore, E: ‘Balaram may eat ants’ is a tantologous statement and can never feature in a valid syllogism. A ‘may’ statement implies ‘may not’ and is always true (tantalogous), and can always stand on its own, without any supporting premises. Hence, such a statement is of no use to a student of logic, who is concerned with the process of reasoning, arriving at a definite conclusion from definite information given in the premises.
7. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. All actors are handsome.
B. Some actors are popular.
C. Ram is handsome.
D. Ram is a popular actor.
E. Some popular people are handsome.
- (a)
ACD
- (b)
ABE
- (c)
DCA
- (d)
EDC
Answer: Option
B
Text Explanation :
(b) ABE is the correct answer choice, as it forms a valid syllogism.
H = Handsome people
A = Actors
P = Popular people
The shaded portion are some popular people who are actors and hence are handsome people.
All actors are handsome and some of those actors are also popular. Therefore, some who are popular
are also handsome.
(a) ACD is invalid, as there are four terms: actors, handsome people, Ram and popular actors.
Furthermore, just because Ram is handsome does not definitely mean that he is an actor, let alone ‘a popular
actor’.
(c) and (d) are similarly invalid as option (a), because they each have four terms.
8. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. Modern industry is technology-driven.
B. BTI is a modern industry.
C. BTI is technology-driven.
D. BTI may be technology-driven
E. Technology driven industry is modern.
- (a)
ABC
- (b)
ABD
- (c)
BCA
- (d)
EBC
Answer: Option
A
Text Explanation :
(a) ABC is the correct answer choice, as it forms a valid syllogism.
BTI = BTI
MI = Modern Industry
TD = Thing that is technology-driven
All modern industries are technology-driven.
BTI is a modern industry
Therefore, BTI is technology-driven.
(b) ABD is invalid, although it is similar to the correct option ABC.
It is invalid simply because the statement D: ‘BTI may be technology-driven, is a tantalogous statement (that
is, it is always true, regardless of what the premises say).
(c) BCA is invalid. Just because BTI is a modern industry and it is technology-driven, it does not mean that all MI are TD. It would, however, be valid to conclude that ‘Some MI are TD’.
(d) EBC is invalid, because if BTI is a modern industry, we cannot definitely conclude that it is technologydriven, as evident from the Venn diagram.
9. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. All Golmal islanders are blue-coloured people.
B. Some smart people are not blue-coloured people.
C. Some babies are blue-coloured.
D. Some babies are smart.
E. Some smart people are not Golmal islanders.
- (a)
BCD
- (b)
ABE
- (c)
CBD
- (d)
None of these
Answer: Option
B
Text Explanation :
(b) ABE is the correct answer choice, as it forms a valid syllogism.
GI = Golmal islanders
BCP = Blue-coloured people
SP = Smart people
NBCP = Not blue-coloured people
Those smart people who are not blue-coloured people (shaded portion) are definitely not Golmal islanders.
(a) BCD is invalid, because there is no connection between some babies that are BCP and the some SP
who are not BCP.
(c) CBD is invalid, because there need not necessarily be any relationship between the some B that are BCP
and the some B that are SP.
10. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question consists of five statements followed by options consisting of three statements put together in a specific order. Choose the option which indicates a valid argument, that is, where the third statement is a conclusion drawn from the preceding two statements.
Example:
A. All cigarettes are hazardous to health.
B. Brand X is a cigarette.
C. Brand X is hazardous to health.
Here, ABC is a valid option, where statement C can be concluded from statements A and B.
A. MBAs are in great demand.
B. Ram and Sita are in great demand.
C. Ram is in great demand.
D. Sita is in great demand.
E. Ram and Sita are MBAs.
- (a)
ABE
- (b)
ECD
- (c)
AEB
- (d)
EBA
Answer: Option
C
Text Explanation :
(c) AEB is the correct answer choice, as it forms a valid syllogism.
R + S = Ram and Sita
PGD = People in great demand
MBA = MBA
As all MBAs are in great demand and Ram and Sita belong to the set of MBAs, Ram and Sita are also in
great demand.
(a) ABE is invalid because R + S need not be MBAs, just because both are in great demand.
(b) ECD makes no sense.
(d) EBA is invalid. Just because R + S are MBAs and in great demand does not mean that ‘all MBAs are in
great demand’. It would, however, be valid to conclude the ‘some MBAs are in great demand’.
11. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a main statement followed by four statements labelled A, B, C and D. Choose the ordered pair of statements where the first statement implies the second, and the two statements are logically consistent with the main statement.
Either the orangutan is not angry, or he frowns upon the world.
A. The orangutan frowns upon the world.
B. The orangutan is not angry.
C. The orangutan does not frown upon the world.
D. The orangutan is angry.
- (a)
CB only
- (b)
DA only
- (c)
AB only
- (d)
CB and DA
Answer: Option
D
Text Explanation :
The main statement clearly states that if the orangutan
(O) belongs to the set of not angry (NA), he cannot belong to the set of frowns (F). Also, O must belong to either of the two sets.
CB states that O is not F and is NA. And DA states that O is not NA and is F. Therefore, both CB and DA are logically valid.
12. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a main statement followed by four statements labelled A, B, C and D. Choose the ordered pair of statements where the first statement implies the second, and the two statements are logically consistent with the main statement.
Either Ravana is a demon, or he is a hero.
A. Ravana is a hero.
B. Ravana is a demon.
C. Ravana is not a demon.
D. Ravana is not a hero.
- (a)
CD only
- (b)
BA only
- (c)
CD and BA
- (d)
Db and CA
Answer: Option
D
Text Explanation :
The main statement clearly states that Ravana (R) is either a demon (D) or a hero (H). He has to be at least
one of the two, and if he is one, he cannot be the other.
DB states that R is not H but is D.
And CA states that R is not D but is H.
Therefore, both DB and CA are logically valid.
13. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a main statement followed by four statements labelled A, B, C and D. Choose the ordered pair of statements where the first statement implies the second, and the two statements are logically consistent with the main statement.
Whenever Rajeev uses the Internet, he dreams about spiders.
A. Rajeev did not dream about spiders.
B. Rajeev used the Internet.
C. Rajeev dreamt about spiders.
D. Rajeev did not use the Internet.
- (a)
AD
- (b)
DC
- (c)
CB
- (d)
DA
Answer: Option
A
Text Explanation :
The question statement clearly states that whenever Rajeev uses the Internet, he dreams about spiders.
However, this does not mean that he dreams about spiders only when he uses the Internet. Therefore,
using the Internet is only one possible condition for Rajeev to dream about spiders. Thus, the Venn diagram
for the question will be:
Where,
UI → Uses Internet
DS → Dreams of spiders
Answer choice (a) AD states that Rajeev did not dream about spiders, and hence he did not use the Internet.
This logically follows the above Venn diagram. If the main set does not occur, the subset will also not occur.
Thus, AD is the right option.
14. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a main statement followed by four statements labelled A, B, C and D. Choose the ordered pair of statements where the first statement implies the second, and the two statements are logically consistent with the main statement.
If I talk to my professors, then I do not need to take a pill for headache.
A. I talked to my professors.
B. I did not need to take a pill for headache.
C. I needed to take a pill for headache.
D. I did not talk to my professors.
- (a)
AB only
- (b)
DC only
- (c)
CD only
- (d)
Ab and CD
Answer: Option
D
Text Explanation :
P = I talk to my professors
Q = I do not need to take a pill for headache.
Therefore, both AB(P ⇒ Q) and CD(neg Q ⇒ neg P) are logically consistent, not BA and DC.
(d) ‘AB and CD’ is the correct answer choice.
15. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. No cowboys laugh. Some who laugh are sphinxes. Some sphinxes are not cowboys.
B. All ghosts are florescent. Some ghost do not sing. Some singers are not florescent.
C. Cricketers indulge in swearing. Those who swear are hanged. Some who are hanged are not cricketers.
D. Some crazy people are pianists. All crazy people are whistlers. Some whistlers are pianists.
- (a)
A and B
- (b)
C only
- (c)
A and D
- (d)
D only
Answer: Option
C
Text Explanation :
(c) ‘A and D’ is the correct answer choice
Statement A is valid:
The shaded portion represents those some sphinxes that laugh and, therefore, are not cowboys as no cowboys laugh.
Statement B is invalid.
All G are F.
Some G are not S.
∴ Some S are not F.
F = Florescent things
G = Ghosts
S = Singers
The valid conclusion is: Some F(shared position) are not S. (V) and not the converse: Some S are not F. (X)
(The some ghosts who are not singers (in shaded portion) are also the ‘some florescent things that are not singers’)
Statement C is invalid:
All C are S.
All S are H.
∴ Some H are not C.
C = Cricketers
S = Those who swear
H = Those who are hanged
The valid conclusion is:
All C are H () and not its negation: Some H are not (C) (x)
Statement D is valid.
Some CP are P.
All CP are W.
∴ Some W are P.
CP = Crazy people
W = Wrestlers
P = Pianists
The shaded portion represents those some pianists who are crazy people and are, therefore, wrestlers.
And conversely, they are those some wrestlers who are pianists.
16. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. All good people are knights. All warriors are good people. All knights are warriors.
B. No footballers are ministers. All footballers are tough. Some ministers are players.
C. All pizzas are snacks. Some meals are pizzas. Some meals are snacks.
D. Some barkers are musk deer. All barkers are sloth bears. Some sloth bears are musk deer.
- (a)
C and D
- (b)
B and C
- (c)
A only
- (d)
C only
Answer: Option
A
Text Explanation :
(a) ‘C and D’ is the correct answer choice.
Statement A is invalid: The valid conclusion would be ‘All W are K’, rather than its converse, ‘All K are W’.
K = Knights
GP = Good People
W = Warriors
Statement B is invalid, because it has four terms:
footballers, ministers, tough people and players.
Statement C is valid: The ‘some M’ that are P are also S.
(shaded position).
S = Snacks
P = Pizzas
M = Meals
Statement D is valid: The ‘some MD’ that are B are also
SB. (shaded portion).
SB = Sloth bears
B = Barkers
MD = Musk deer
17. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. Dinosaurs are prehistoric creatures. Water-buffaloes are not dinosaurs. Water-buffaloes are not
prehistoric creatures.
B. All politicians are frank. No frank people are crocodiles. No crocodiles are politicians.
C. No diamond is quartz. No opal is quartz. Diamonds are opals.
D. All monkeys like bananas. Some GI Joes like bananas. Some GI Joes are monkeys.
- (a)
C only
- (b)
B only
- (c)
A and D
- (d)
B and C
Answer: Option
C
Text Explanation :
(b) B only is the correct answer choice.
Statement A is invalid, as ‘No WB are PC’ cannot be validly concluded. What can, however, be validly concluded is that ‘Some PC (which are all D in shaded position) are not WB’.
D = Dinosaurs
PC = Prehistoric creatures
WB = Water buffaloes
Statement B is valid as evident from the Venn diagram
F = Frank creatures
P = Politicians
C = Crocodiles
P is a subset of F.
F and C are disjoint sets.
As the main set F can never intersect with C, the subset D will also never intersect or coincide with C.
Statement C is invalid: No valid conclusion can follow from two negative premises, as negatives have the
effect of separating one term from the others.
Statement D is invalid, as the ‘Some GI Joes’ who like bananas need not be monkeys.
18. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. All earthquakes cause havoc. Some landslides cause havoc. Some earthquakes cause landslides.
B. All glass things are transparent. Some curios are glass things. Some curios are transparent.
C. All clay objects are brittle. All XY are clay objects. Some XY are brittle.
D. No criminal is a patriot. Ram is not a patriot. Ram is a criminal.
- (a)
D only
- (b)
B only
- (c)
C and B
- (d)
A only
Answer: Option
C
Text Explanation :
(c) ‘C and B’ is the correct answer choice.
Statement A is invalid because it has four terms:
a. Earthquakes
b. Things that cause havoc
c. Landslides
d. Things that cause landslides
Statement B is valid as the ‘Some C’ which are GT are also T (shaded portion).
T = Transparent
GT = Glass things
C = Curios
As all glass things (GT) are transparent (T), those curios (C) that are GT are definitely T.
Statement C is valid:
B = Brittle things
CO = Clay objects
CO is a subset of B.
XY is a subset of CO.
Therefore, XY is also a subset of B.
Thus, all XY are also brittle.
Statement D is invalid.
No valid conclusion can follow from two negative premises, as negatives have the effect of separating one term from the other.
19. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. MD is an actor. Some actors are pretty. MD is pretty.
B. Some men are cops. All cops are brave. Some brave people are cops.
C. All cops are brave. Some men are cops. Some men are brave.
D. All actors are pretty ; MD is not an actor ; MD is not pretty.
- (a)
D only
- (b)
C only
- (c)
A only
- (d)
B and C
Answer: Option
B
Text Explanation :
(b) C is the only correct answer choice.
Statement A is invalid.
MD need not necessarily be among the some actors who are pretty.
Statement B is invalid, as the third segment is not a conclusion logically deduced using both the first and second segments. In fact, the conclusion can directly be deduced from the second segment alone. Another way to check for this error is to see whether the middle term ‘Cops’, that appears in the premises also appears in the conclusion. Here, ‘Cops’ appears in all three segments and option (b) is therefore, not a valid syllogism.
Statement C is valid. Those ‘Some men’, who are cops are also brave people (shaded portion).
BP = Brave people
C = Cops
M = Men
C is a subset of BP
Some M is C.
Therefore, those M that are C, are also BP.
Statement D is invalid, MS may still be pretty without being an actor.
20. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. All IIMs are in India. No BIMs are in India. No IIMs are BIMs.
B. All IIMs are in India. No BIMs are in India. No BIMs are IIMs.
C. Some IIMs are not in India. Some BIMs are not in India. Some IIMs are BIMs.
D. Some IIMs are not in India. Some BIMs are not in India. Some BIMs are IIMs.
- (a)
A and B
- (b)
C and D
- (c)
A only
- (d)
B only
Answer: Option
A
Text Explanation :
(a) ‘A and B’ is the correct answer choice.
A and B are both valid: ‘No IIMs are BIMs’ or its converse,
‘No BIMs are IIMs’ are both equally valid.
II = Institutes in India.
IIMs is a subset of II.
No II is a BIM
As the mainset II can never intersect with the disjoint set BIM, the subset IIM will also never intersect or
coincide with BIM.
C and D are both invalid: The ‘Some IIMs’ and the ‘Some BIMs’ need not have any relationship between them,
just because they are not in India.
21. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. Citizens of Yes Islands speak only the truth. Citizens of Yes Islands are young people. Young people speak only the truth.
B. Citizens of Yes Islands speak only the truth. Some Yes Islands are in Atlantic. Some citizens of Yes Islands are in the Atlantic.
C. Citizens of Yes Islands speak only the truth. Some young people are citizens of Yes Islands. Some young people speak only the truth.
D. Some people speak only the truth. Some citizens of Yes Islands speak only the truth. Some people who speak only the truth are citizens of Yes Islands.
- (a)
A only
- (b)
B only
- (c)
C only
- (d)
D only
Answer: Option
C
Text Explanation :
(c) Only C is the correct answer choice.
Statement A is invalid. We cannot conclude about ‘all YP’, but only about ‘Some YP’ (shaded portion) who are, incidentally, ‘all CY’.
CYI = Citizens of Yes Islands
ST = People who speak only the truth
YP = Young people
Statement B is invalid, because it has four terms:
a. Citizens of Yes Islands
b. People who speak only the truth
c. Things that are in the Atlantic
d. Yes Islands
Statement C is valid. The ‘Some YP’ who are CYI also are people who speak only the truth. (shaded portion)
Statement D is invalid, because the ‘some people’ and the ‘some CYI’ need not have any relationship between them, just because both speak only the truth.
22. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. All mammals are viviparous. Some fish are viviparous. Some fish are mammals.
B. All birds are oviparous. Some fish are not oviparous. Some fish are birds.
C. No mammal is oviparous. Some creatures are oviparous and some are not. Some creatures are not mammals.
D. Some creatures are mammals. Some creatures are viviparous. Some mammals are viviparous.
- (a)
A only
- (b)
B only
- (c)
C only
- (d)
D only
Answer: Option
C
Text Explanation :
(c) C only is the correct answer choice.
Statement A is invalid, as the some fish that are viviparous need not be mammals.
Statement B is invalid. We can validly conclude that the ‘Some fish (shaded portion)’ that are not oviparous are definitely not birds as well. But, based on this, we cannot conclude that ‘Some fish are birds’, as we have no knowledge about the ‘remaining fish’.
Statement C is valid, as we can validly conclude that the ‘Some C’ which are inside the circle O cannot be mammals. But nothing definite can be said about the ‘Some C’ which are outside the circle O.
Statement D is invalid, because the ‘Some C’, which are V and the ‘Some C’, which are M, need not have any relationship between them, as evident from the Venn diagram.
23. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. Many singers are not writers. All poets are singers. Some poets are not writers.
B. Giants climb beanstalks. Some chicken do not climb beanstalks. Some chicken are not giants.
C. All explorers live in snowdrifts. Some penguins live in snowdrifts. Some penguins are explorers.
D. Amar is taller than Akbar. Anthony is shorter than Amar. Akbar is shorter than Anthony.
- (a)
A only
- (b)
B only
- (c)
B and C
- (d)
D only
Answer: Option
B
Text Explanation :
(b) B only is the correct answer choice.
Statement A is invalid, as no definite relationship between P and W can be established.
Note: ‘Many’ is translated as ‘Some’ to convert the statement in standard form.
The ‘Some S (shared portion)’ are not W, but some other S could be W, as shown in the Venn diagram above.
Statement B is valid, as the ‘Some C (shaded portion)’ that do not climb beans stalks cannot be giants.
G = Grants
C = Children
CB = Creatures which climb beanstalks
C is invalid, the ‘Some penguins’ that live in snowdrifts need not be explorers.
D is invalid, as Amar is the tallest among the three, but it is not clear how the heights of Akbar and Anthony are compared.
Note: This is not a ‘Categorical’ syllogism comprising statements, as such. All S is P, No S is P, Some S is P and some S is not P. It is a ‘relational’ syllogism comprising relational statements that normally feature in analytical reasoning. Be alert: CAT examiner is in the habit of jumbling up questions to throw you off gear.
24. CAT 1999 LRDI | LR - Syllogisms CAT Question
Directions: Each question has a set of four statements. Each statement has three segments. Choose the alternative where the third segment in the statement can be logically deduced using both the preceding two, but not just from one of them.
A. A few farmers are rocket scientists. Some rocket scientists catch snakes. A few farmers catch snakes.
B. Poonam is a kangaroo. Some kangaroos are made of teak. Poonam is made of teak.
C. No bulls eat grass. All matadors eat grass. No matadors are bulls.
D. Some skunks drive Cadillacs. All skunks are polar bears. Some polar bears drive Cadillacs.
- (a)
B only
- (b)
A and C
- (c)
C only
- (d)
C and D
Answer: Option
D
Text Explanation :
(d) ‘C and D’ is the correct answer choice.
Statement A is invalid: The ‘Some F’ who are RS and the ‘Some RS’ who can catch snakes need not have any relationship between them.
CS = People who catch snakes
RS = Rocket scientists
F = Farmers
Note: ‘Many’ or ‘a few’ are both translated as ‘some’ to convert the statements in the standard form.
Statement B is invalid. Poonam need not be among the some kangaroos that are made of teak.
Statement C is valid. No matadors can be bulls because the former eat grass, while the latter do not.
EG: Creatures that eat grass
M: Matadors
B: Bulls
Statement D is valid. The some PB (shaded portion) are in effect the ‘Some skunks’ that drive Cadillacs.
DC: Creature that drive Cadillacs
PB: Polar bears
S: Skunks
25. CAT 1998 LRDI | LR - Syllogisms CAT Question
Direction: The question contains four arguments of three sentences each. Choose the set in which the third statement is a logical conclusion of the first two.
A. Some Xs are Ps. Some Ps are Ys. Some Xs are Ys.
B. All Sonas are bright. Some bright are crazy. Some Sonas are crazy.
C. No faith is strong. Only strong have biceps. No faith has biceps.
D. All men are weak. Some weak are strong. Some strong are weak.
- (a)
A and D
- (b)
C only
- (c)
D only
- (d)
None of these
Answer: Option
B
Text Explanation :
If only strong have biceps and no faith is strong, it follows that no faith has biceps. In A, X and Y need not overlap. In B, the Sona and crazy set need not overlap. In D there is no logical conclusion at all.
Solution
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