A train travelled at one-thirds of its usual speed, and hence reached the destination 30 minutes&nbsp;after the scheduled time. On its return journey, the train initially travelled at its usual speed for 5&nbsp;minutes but then stopped for 4 minutes for an emergency. The percentage by which the train&nbsp;must now increase its usual speed so as to reach the destination at the scheduled time, is nearest&nbsp;to

CAT 2020 Question Paper | CAT Verbal Ability Slot 1

Question :

A train travelled at one-thirds of its usual speed, and hence reached the destination 30 minutes after the scheduled time. On its return journey, the train initially travelled at its usual speed for 5 minutes but then stopped for 4 minutes for an emergency. The percentage by which the train must now increase its usual speed so as to reach the destination at the scheduled time, is nearest to

Started 5 days ago by Shashank in

0 10

A.
61
B.
50
C.
58
D.
67

Option D is the correct answer.

Explanatory Answer

Original speed = S & Original time = T
New Speed = S/3, speed and time are inversely proportional hence New time = 3T
The difference between times = 3T-T = 30 mins
Original time taken = 15 mins
Assume Distance is 15 Kms and Speed = 1 km/hr

In 5 mins the train travelled 5 kms and 4 mins it stopped.
In 6 mins it has to cover 10 kms
The original speed will be increased by a factor of 1.66 or 67%