Question

The distance between two places $A$ and $B$ on road is $70$ kilometers. A car starts from $A$ and the other from $B$. If they travel in the same direction, they will meet after $7$ hours. If they travel towards each other they will meet after $1$ hour, then find their speeds.

Answer 1

R.E.F.Image.

Time t

For (A)

$\frac{70+d}{t}=u_A$

$\Rightarrow t=7hrs$

$\therefore 70+d=7u_A$

For (B)

$\frac{d}{t}=u_B$

$d=7u_B$

$d_1+d_2=70$

$\Rightarrow u_{A}t+u_{B}t=70$

$\Rightarrow u_A+u_B=70$ __(1)

Hence, $70+7u_B=u_A$

$\Rightarrow u_A=u_B+10$ __ (2)

solving $e{q}^{ns}$ (1) & (2)

$u_B=30km/hr$

$u_A=10km/hr$