A bicyclist travels uphill from town A to town B for 2…

A bicyclist travels uphill from town A to town B for 2 hours at an average speed of 4 miles per hour and returns along the same road at an average speed of 5 miles per hour. What is the bicyclist’s average speed for the round trip, in miles per hour?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #17186