Question

A train travelling at 60 kmph, crosses a bike which is speeding at 30 kmph in the opposite direction in 20 sec. Find the time taken by the train to cross another bike travelling at 24 kmph in the same direction as the train does.
1. 60 sec
2. 20 sec
3. 50 sec
4. 25 sec

Answer 1

Correct Answer - Option 3 : 50 sec

CALCULATION:

1^st bike and train are travelling in opposite direction 

⇒ Relative speed = 60 + 30 = 90 kmph = 25 m/sec

⇒ Length of train = 25 × 20 = 500 m

2^nd bike and train are travelling in same direction 

⇒ Relative speed = 60 - 24 = 36 kmph = 10 m/sec

⇒ Time taken = 500/10 = 50 sec

We will consider the length of the bike as negligible, as it is very small as compared to the length of the train.