Question

The length of a circular track is 1 km. Shruti and Kavya started from the same point on the track and ran in opposite directions at 13m/s and 17 m/s respectively. They kept running for 25 minutes. How many times did they cross each other?
1. 27
2. 54
3. 45
4. 36

Answer 1

Correct Answer - Option 3 : 45

Let Shruti and Kavya cross each other for first time after t seconds.

As we know, relative speed = 13 + 17 = 30 m/s

Then t = 1000/30 = 100/3 s

Thus, number of times they will cross each other = (25 × 60)/(100/3) = 45 times