Question

A car covers the first half of the distance between two places at a speed of 40kmph

and the second half at 60kmph. Calculate the average speed of the car.​

Answer 1

Explanation:

Let the distance between the 2 places be 2d

In first half ,

distance , d1 = d

speed , s1 = 40 kmph

time taken , t1 = d1/s1 = d/40 h

In second half ,

Distance covered , d2 = d

Speed , s2 = 60 kmph

Time taken , t2 = d2/s2 = d/60 h

$average \: speed = \frac{d1 + d2}{t1 + t2}$

$= \frac{d + d}{ \frac{d}{40} + \frac{d}{60} } = \frac{2d}{ \frac{3d + 2d}{120} } = \frac{2d}{ \frac{5d}{120} } = 48 \: kmph$

Therefore , it is your answer.

I hope it helps you . If you have any doubts, then don't hesitate to ask.