Question

An express train makes a run of 240 km at a certain speed another train who speed is 2 km/h less takes an hour longer to cover the same distance find the speed of the express train in kilometre per hour

Answer 1

Answer:

total distance = 240 km

let speed = x km/hr

therefore time = 240/x hrs

new speed = x-12 km/hr

therefore time = 240/x-12 hrs

given difference = 1 hr

therefore 240/x-12 - 240/x=1

240x-240x+2880/x2-12x =1

2880 = x2-12x

x2-12x-2880=0

by completing the squares

x=60 or x = -48

speed is non negetive

therefore original speed of train = 60 km/hr

Step-by-step explanation:

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