Question

A travel from A to B at a vellocity 36kmh and return at a vellocity 72kmh find average speed​

Answer 1

Answer:

48km/hr

Explanation:

Here, the distance is same. d=d1=d2

$average \: velocity \: = \frac{total \: distance}{total \: time}$

$av = \frac{2d}{t1 + t2}$

$t1 = \frac{d}{v1} \: \: \: \\ t2 = \frac{d}{v2}$

$t1 + t2 = \frac{(d)(v2 + v1)}{v1 \times v2}$

put t1 + t2 in av.

$av = \frac{2d(v1 \times v2)}{d(v2 + v1)}$

$av = \frac{2(v1 \times v2)}{(v2 + v1)} \\ = \frac{2(72 \times 36)}{(72 + 36)}$

$= 48kmhr$