On a trip, a cyclist averaged 8 miles per hour for the…

On a trip, a cyclist averaged 8 miles per hour for the first 12 miles and 12 miles per hour for the remaining 24 miles. If the cyclist returned immediately via the same route and took a total of 7.5 hours for the round trip, what was the average speed (in miles per hour) for the return trip?

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 #1759