Question

An express train makes a run of 240km at a certain speed. another train 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

Step-by-step explanation:

let x=speed of express train

x-12=speed of slower train

travel time=distance/speed

..

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

LCD: x(x-12)

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

x^2-12x-2880

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

x=-48(reject x>0)

or

x=60

ans:

Speed of the express train=60 km/hr