A car travels the first 1/3 of certain distance with a speed…

A car travels the first 1/3 of certain distance with a speed of 10km/hr the next 1/3 distance with a speed of 20 km/hr, and the last 1/3 distance with a speed of 10 km/hr. the average speed of the car for the whole journey 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 #61587