Question

a car covers half the distance at a speed of 50 kmph and the other half at 40kmph .find the average speed of car

Answer 1

Answer:

Avg speed=44.44km/h

Explanation:

Speeds for 1st half= 50km/h

2nd half= 40 km/h

Let total distance to be travelled=2s km (skm at 50km/h + skm at 40 km/h)

We know,  

time=dist/speed, t=s/v

t for 1st half= t₁=s/50  

t for 2nd half= t₂=s/40

Now, we know, Average speed= Total dist/Total time

Avg speed= 2s/(t₁+t₂)

=2s/(s/50 + s/40)

=2s/[(4s+5s)/200]

=2s*200/9s

=2*200/9

=44.44km/h