Zoey took 2.5 hours to bike the 60 km from her house to the beach. It took her 3.5 hours to bike the same distance back to her house. What was Zoey's average speed?
Average speed =Distance / time
=(60 x 2) / (2.5 + 3.5)
=120 / 6
= 20 km/h - her average speed to the beach and back.