A train passes a man in 10 seconds and a platform 100 m long in 14 seconds. Find the speed of the train.

Distance = speed × time

Given, train passes a man in 10 seconds

Thus it travels its own length in 10s

Length = speed × 10

Also given, it crosses a 100m platform in 14s i.e it crosses its length and length of platform in 14 sec

∴ length + 100 = speed × 14

Subtracting both equations, we get

100 = speed × 4

⇒ speed = 25 m/s

⇒ speed = 25 × 18/5 = 90 km/hr