Question

A train travels 360 km at a uniform speed if the speed had been 5km hr more it would have take one hour less for the same journey find the speed of the train

Answer 1

distance = 360 km

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let speed be x

then time taken = d/r

t=360/x

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if speed is increased by 5 km/h

speed will be (x+5)km/h

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distance is the same

t= 360/(x+5)

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time with original speed - time with increased speed = 1

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

LCD= x(x+5)

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

360x+1800-360x=x(x+5)

x^2+5x = 1800

x^2+5x-1800=0

x^2+45x-40x-1800=0

x(x+45)-40(x+45)=0

(x-40)(x+45)=0

x= 40 mph the original speed.