A car driver travels from the plains to the hill station, which…

A car driver travels from the plains to the hill station, which are 200 km apart at an average speed of 30km/hr. in return trip, he covers the same distance at an average speed of 20km/hr. the average speed of the car over the entire distance of 400 km is

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 #8876