distance d from home to college
total distance = 2 d
time to college = d/20
time to get back = d/40
total time driving = d/20 + d/40
average speed = 2d/(d/20+d/40)
= 80/(2+1) = 80/3 = about 27 km/h
A student goes to college,driving his car at 20 km per hour. He returns though same route ,driving at 40 km per hour . Find average speed during entire journey
1 answer
1 answer