Average speed of a car on a trip.

Question

A car travels for an hour at a speed of 20 km/hr, the next two hours at a speed of 65 km/hr and the final hour at a speed of 85 km/hr. What is the average speed of the car for the entire trip?

Answer 1

Car travel = (20 km/hour)(1 hour) + (65 km/hour)(2 hour) + (85 km/hour)(1 hour) = 20 km + 130 km + 85 km = 235 km

 

Average speed = distance/time = (235 km)(4 hours) = 58.75 km/hr