Question

Natalie draw to the ferry office and back. The trip took five hours and the trip back took four hours. She average 80 km/h on the return trip. Find the average speed of the trip there.

Answer 1

Draw? Didn't Natalie DRIVE to the office and then back?

Average speed = total distance divided by total time.

Total distance = speed times time = 80 km/hr times 4 hours, or 320 km.

Then, back to the main question:

Total distance = 2(320 km)
Total time elapsed = 9 hrs
640 km
Average speed = ------------- = 71.1 km/hr
9 hrs