Question

what is the average speed of a car if it covers half distance with 60km per hour-1 speed and other half with 40km per hour-1 speed?

Answer 1

Explanation:

Letx consider, x= total distance covered by the car,

Time taken to complete the half distance with velocity v=40km/h,t 1= 2×40x = 80x

hr. . . . .(1)

The time taken to complete another half distance with velocity u=60km/ht 2= 2×60x= 120hr

The total time taken, t=t

1+t 2t= 80x+ 120x=

48

x

hr

The average speed of the car,

v

avg

=

x/48

x

=48km/h

The correct option is B.