Question

A fast train takes 3 hours less than a slow train for a journey of 600 km if the speed of the slow train is 10 km per hour less than that of fast train find the speed of two trains

Answer 1

Let the speed of the fast train be x km/hr

Let the speed of the slow train be (x- 10) km/hr

Hence the time taken by the fast train is 600/x

Time taken by slow train is 600/(x-10)

Therefore (600/x-10) - (600/x) = 3

On reducing we get,

3x^2 -30x-6000 = 0 or x^2 -10x -2000 = 0

On factorising we get x = 50 or -40

The negative value is not acceptable.

Hence x = 50

That is the speed of the fast train is 50km/hr and the speed of the slow train is 40km/hr