Question

An express train makes a run of 240 km at a certain speed another trin whose speed is 12km/hr less takes an hour longer to cover the same distance . find the speed of the express train in km/hr.

Answer 1

Answer:

let x = speed of express train and

(x-12) = speed of slower train

Time = Distance/Speed

..

240/(x-12)-240/x=1

240x- 240(x-12) = x(x-12)

240x-240x+2880=x^2-12x

x^2-12x-2880=0

(x+48)(x-60)=0

x=-48(reject x>0)

or

x=60

ans:

Speed of the express train=60 km/hr