posted by June .
19. A family takes a car trip. They travel for an hour at 80 km/h and then for 2 hours at 40 km/h. Find the average speed. (Hint, Remember to consider the total distance and the total amount of time.)
Do exactly what their hint suggests,
distance of first part = 1(80) or 80 miles
distance of 2nd part = 2(4) or 80 miles
total distance = 160 miles
total time = 3 hours
avg speed = 160/3 or 53.33.. miles/hr