Question

Find the speed in each case :
A train covers $300km$ in $4$ hours.

Answer 1

We have,

Distance covered $=300km$

Let, the speed of the train $=xkm$

$\therefore t_1=\frac{300}{x}....\left(1\right)$

$Distance=300km$

$Speed=(x-10)km$

$\therefore t_2=\frac{300}{(x-10)}....\left(2\right)$

Given eqn $\left(1\right)-\left(2\right)=1hr$

$\therefore \frac{300}{(x-10)}-\frac{300}{x}=1$

$\frac{[300x-300(x-10\left)\right]}{(x-10)x}=1$

$300x-300x+3000=(x-10)x$

$3000=(x-10)x$

Let, $x=60$

$\therefore 3000=(60-10)60$

Therefore speed of the train $\left(x\right)=60km/hr$