Q.

A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.

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Detailed Solution

Given distance = 360 km

Consider x as the speed, then the time taken

t =360x

If the speed is increased by 5 km/h, new speed will be (x + 5) km/h

Distance will be the same

t = 360x+5

We know that

Time with original speed – Time with increased speed = 1

360x – 360x+5 = 1

360(x+5)-360xx(x+5) = 1

360x + 1800 – 360x = x(x + 5)

x2 + 5x = 1800

x2 + 5x – 1800 = 0

x2 + 45x – 40x – 1800 = 0

x(x + 45) – 40(x + 45) = 0

(x – 40)(x + 45) = 0

x = 40 km/hr

As we know, the value of speed cannot be negative.

Therefore, the speed of the train is 40 km/h.

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A train travels 360 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less for the same journey. Find the speed of the train.