Three taps A,B and C can fill a tank in 10,20 and…

Three taps A,B and C can fill a tank in 10,20 and 30. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in?

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 #75497