Question

Two boys A and B start at the same time to ride from Delhi to Meerut , $60km$ away.A travels $4$ hour slower than B.B reaches Meerut and at once turns back meeting A $12$,km from Meerut Find A's speed ?

• A. $6$ km/hr
• B. $4$ km/hr
• C. $8$ km/hr
• D. $10$ km/hr

Answer 1

The correct option is C $8$ km/hr

Let the speed of B$=x$ km/h

speed of A$=(x-4)$km/h

Distance travelled by A$=60-12=48$km

Distance travelled by B$=60+12=72$km

Time will be same in both cases

$T_1=\frac{48}{x-4}$

$T_2=\frac{72}{x}$

So

$\Rightarrow \frac{48}{x-4}=\frac{72}{x}$

$48x=72x-288$

$48x-72x=-288$

$-24x=-288$

$x=\frac{288}{24}$

$x=12$

So speed of A$=x-4$

$=12-4$

$=8$ km/h Answer.