Discussion

Explanation:

The speed of the car in the fourth gear is five times its speed in the first gear
⇒ Let the speed in 1st gear be x kmph, hence speed in 4th gear will be 5x kmph.

The car takes twice the time to travel a certain distance in the second gear as compared to the third gear
⇒ Speed in 3rd gear is twice the speed in 2nd gear.
⇒ Let speeds in 2nd and 3rd gears be y & 2y kmph.

In a 100 km journey, if Vinita travels equal distances in each of the gears, she takes 585 minutes
⇒ 25/x + 25/5x + 25/y + 25/2y = 585/60
⇒ 25/x + 5/x + 50/2y + 25/2y = 39/4
⇒ 30/x + 75/2y = 39/4
⇒ 60/x + 75/y = 39/2
⇒ 20/x + 25/y = 13/2
⇒ 5(4/x + 5/y) = 13/2
⇒ 4/x + 5/y = 13/10  ...(1)

Now, we need to find the time taken if Vinita travels 4, 4, 32, 60 kms at 1st, 2nd, 3rd & 4th gear respectively.
⇒ 4/x + 4/y + 32/2y + 60/5x
= 4/x + 4/y + 16/y + 12/x
= 16/x + 20/y
= 4(4/x + 5/y)
= 4 × 13/10
= 5.2 hours
= 5.2 × 60 minutes
= 312 minutes

Hence, 312.

» Your doubt will be displayed only after approval.


Doubts


Feedback

Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.


© 2024 | All Rights Reserved | Apti4All