Practice Questions for Ratio, Proportion & Variation

26. CRE 1 - Ratio | Ratio, Proportion & Variation

A is twice of B and three times B is equal to four times C. The ratio among A, B and C is :

(a)
3 : 4 : 8
(b)
8 : 4 : 3
(c)
4 : 3 : 8
(d)
None of these

Answer: Option B

Explanation :

A = 2B, 3B = 4C ⇒ C = 3B/4

Then, A : B : C = 2B : B : 3B/4 = 2 ∶ 1 ∶ 3/4 = $2 \times 4 : 1 \times 4 : \frac{3 \times 4}{4}$ = 8 ∶ 4 ∶ 3.

Hence, option (b).

27. CRE 1 - Ratio | Ratio, Proportion & Variation

If A : B = 2 : 3, B : C = 4 : 3 and C : D = 2 : 5, then, A : B : C : D is?

(a)
16 : 24 : 18 : 45
(b)
16 : 24 : 20 : 50
(c)
30 : 45 : 14 : 35
(d)
None of these

28. CRE 1 - Ratio | Ratio, Proportion & Variation

Rs. 750 is distributed among A, B and C such that A’s share : B’s share = 2 : 3 and B’s share : C’s share = 6 : 5. The share of A is?

(a)
Rs. 150
(b)
Rs. 175
(c)
Rs. 200
(d)
Rs. 250

Answer: Option C

Explanation :

A/B = 2/3 = 4/6 and B/C = 6/5

∴ If A = 4, then B = 6 and C = 5.

⇒ A : B : C = 4 : 6 : 5.

∴ A’s share = $\frac{4}{4 + 6 + 5}$ × 750 = 200

Hence, option (c).

29. CRE 1 - Ratio | Ratio, Proportion & Variation

The speed of three cars is in the ratio 4 : 3 : 2. The ratio between the time taken by the cars to cover the same distance will be:

(a)
2 : 3 : 4
(b)
6 : 8 : 12
(c)
3 : 4 : 6
(d)
None of these

Answer: Option C

Explanation :

Remember speed = distance/time, since distance covered is the same, say d and if t₁, t₂, t₃ be the time taken by the three cars, then,

$\frac{d}{t_{1}} : \frac{d}{t_{2}} : \frac{d}{t_{3}} = 4 : 3 : 2$ or $\frac{1}{t_{1}} : \frac{1}{t_{2}} : \frac{1}{t_{3}} = 4 : 3 : 2$

To find t₁ : t₂ : t₃, we must find inverse ratio of 4 : 3 : 2, i.e. 1/4 : 1/3 : 1/2 = $\frac{1 \times 12}{4} : \frac{1 \times 12}{3} : \frac{1 \times 12}{2}$ = 3 ∶ 4 ∶ 6

Hence, option (c).

CRE 1 - Ratio | Ratio, Proportion & Variation

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