Question

a car covers half the distance at a speed of 50 km per hour and other half at 40 km per hour find the average speed of the car

Answer 1

For this there is a formula

2/v(avg)=1/v1+1/v2

2/v(avg) =(40+50)/40*50

So now you can calculate vavg

Answer 2

Let total distance be D.
Then total time = (D/2)/50+(D/2)/40=9D/400
Therefore avg speed =D/9D*400=44.45km/hr