Question

a train travel 360 km at a uniform speed . if the speed had been 5 km/hr more,it would have taken .1 hour less for the same journey. find the original speed of the train ​

Answer 1

let the original speed be x km/hr

time is equal to 360 × x

new speed (x+5)km/hr

time to cover a distance 360/x+5

Step-by-step explanation:

$\frac{ 360}{x} - \frac{ 360}{x} + 5 = 1 \\ 360 \frac{(x + 5 + x)}{x(x + 5)} = 1 \\ = 360(5) = x {}^{2} + {5}x \\ =1800 = {x}^{2} + 5x \\ = {x}^{2} + 5x - 1800 = 0 \\ = {x}^{2} + 45x - 40 - 1800 = 0 \\ = xx + 45)(x - 40) = 0 \\ = x = ( - 45)(40) \\ = speed \: cannot \: be \: negative \\ so \: x = 40km | h$