Question

A car travells moves a distance of 200m.it cover first half distance at speed 40km/h and second half at speed of v km/h.calculate average speed of car

Answer 1

First time$t_1=\frac{100}{40}$

Second time$t_2=\frac{100}{v}$

Total time

$t=t_1+t_2$

$t=\frac{100}{40}+\frac{100}{v}$

Average speed=$\frac{total distance}{total time}$

$48=\frac{200}{\frac{100}{40}+\frac{100}{v}}$

$\frac{1}{4}+\frac{10}{v}=\frac{20}{48}$

$\frac{1}{4}+\frac{10}{v}=\frac{20}{48}$

$v=60km/h$