Question

A man covers half of the distance with speed v and remaining half of the distance with speed v1 and v2 for equal intervals of time.Then calculate average speed

Answer 1

Average speed=2d

$t1 = \frac{d}{v1} \: t2 = \frac{d}{v2} \\ \\ average \: speed = \frac{2v1v2}{v1 + v2}$