Question

A car moves from A to B with a uniform speed v1, and returns to A with a uniform speed v2. The
average speed for this round trip is
​

Answer 1

Answer:

distance travelled from A to B is = x

and distance travelled from B to A= x

total distance = 2x

time for A to B = distance / speed

= x/ v1

time for B to A = distance / speed

= x/ v2

therefore total time = x/ v1+ x/v2

= x(v1+v2/v1*v2)

Average speed = Total distance / Total time

= 2x/x(v1+v2/v1*v2)

Average speed = 2v1*v2/v1+v2

Explanation:

in last stage the x will cancel each other and final equation for Average speed is

= 2v1*v2/v1+v2