Question

A train covered at a certain distance for 360 km would have taken 48 minutes less if its speed is increased by 5 km find the speed of the train

Answer 1

let speed of train be X

when speed of train is increased x +5

so equation becomes

$\frac{360}{x} - \frac{360}{x + 5} = \frac{4}{5}$

$360( \frac{1}{x} - \frac{1}{x + 5} ) = \frac{4}{5}$

$360( \frac{5}{ {x}^{2} + 5x} ) = \frac{4}{5}$

$1800 \times 5 = 4 {x}^{2} + 20x$

$9000 = 4{x}^{2} + 20x$

$4 {x}^{2} + 20x - 9000$

${x}^{2} + 5x - 2250$

${x}^{2} + 50x - 45x - 2250$

$x(x + 50) - 45(x + 50)$

$(x - 45)(x - 50)$

$x = 45 \: \: \: \: \: x = - 50 \: \: is \: not \: possible$

speed of train = 45km/h

Answer 2

hope it helps you friend.....