Question

A train moving at 96 kmph for a certain length crosses a bridge of length 100 m in 12 seconds while a car moving at a certain speed of length 2 m crosses the same bridge in 51 seconds. In what time will the train cross the car if they are moving in the same direction?
1. 7 seconds
2. 9 seconds
3. 12 seconds
4. 11 seconds
5. 6 seconds

Answer 1

Correct Answer - Option 2 : 9 seconds

Given:

Speed of train = 96kmph = 96 × 5 / 18 = 80 / 3 m / s

Calculation:

Let the speed of the train be A m / s.

Let the length of the train be K m.

⇒ (K + 100) / 12 = 80 / 3

⇒ K = 220m

Then,

⇒ (100 + 2) / A = 51

⇒ A = 2 m / s

Relative speed = 80 / 3 – 2 = 74 / 3 m / s

Required time = (220 + 2) / (74 / 3)

= 9 seconds