Question

A train travels 360km/h at a uniform speed. If the speed was 5km/h more then it would take less time for journey. Find original speed

Answer 1

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student-name Chandrika Rawat asked in Math
a train travels 360 km at uniform speed . if the speed had been 5 km / hr more it would have taken 1 hour less for the same journey. find the speed of the train.

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student-name Cassandra answered this
60 helpful votes in Math, Class XI-Science
Let the speed of the train be x km/h.Distance covered by the train = 360 km

1st case- Time, T1= distance / speed1 = 360 / x

2nd case- Time, T2= distance / speed2 = 360 / x + 5

According to the question,

360 / x - 1 = 360 / x + 5(or) 360 / x - 360 / x + 5 = 1

360 (x+5) -360 (x) / x (x+5) =1

360x + 1800 - 360x / x2 + 5x = 1

1800 = x2 + 5x

x2 + 5x - 1800 =0

( Now u can do any of the methods i.e. factorisation or completing the square method or apply quadratic formula to find the speed.)

Hope You get it....! :)