Question

A train covers a distance of 90 km at a uniform speed. Had the speed been 15 km / hour more, it would have taken 30 minutes less for the journey. Find the original speed of the train.

Answer 1

OKK.

IT IS SOLVED.

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Answer 2

Original Speed of the train is 45 Km/hr.

Step-by-step explanation:

Let the original speed of the train be x. Distance is 90 km.

Given:

90/(x+15) - 90/x = 1/2  as time = distance / speed

2[90x -90(x+15)] = x(x+15)

+2700 = x² + 15x

x² + 15x - 2700 = 0

x² + 60x - 45x - 2000 = 0

x (x + 60) -45 (x + 60) = 0

(x - 45) (x + 60) = 0

So x can be +45 or -60.

Speed can't be negative. So x = +45.

Original Speed of the train is 45 Km/hr.