Question

A car with speed $60km/hr$ takes $8$ hours to travel same distance. What should be the increase in the speed if the same distance is to be covered in $7\frac{1}{2}$ hours?

Answer 1

Given that:

$v_1=60km/hr$, $t_1=8hr$

$v_2=?$, $t_1=\frac{15}{2}hr$

And traveled distance is $d$ in both cases then

$d=60\times 8$ .....(1)

$d=v_2\times \frac{15}{2}$ .....(2)

By equation (1) and (2), we get

$60\times 8$$=v_2\times \frac{15}{2}$

$v_2=32\times 2$

$v_2=64km/hr$

Hence, the speed of car should be increased by $4km/hr$ to cover the same distance.