Question

A train running at 70 km/h passes a person riding parallel to the railway line moving in the opposite direction in 2 seconds. If the rider goes in the same direction, the train takes 5 seconds to pass him. What is the speed of the rider?

पर्याय

• 30 km/h

• 40 km/ h

• 10 km/h

• 20 km/h

Answer 1

30 km/h

Explanation:

Suppose speed of man 'x' km/h.

Take length of man is negligible.

So distance travel by train to cross man from both opposite and same side will be equal.

`(70 + x) xx 5/18 xx 2 = (70 - x) xx 5/18 xx 5`

⇒ `140 + 2x = 350 - 5x`

⇒ `7x = 210`

⇒ `x` = 30 km/h