Two pipes can fill a tank in 10 hours and 12 hours

Two pipes can fill a tank in 10 hours and 12 hours. While the 3rd pipe empties the full tank in 20hours. If all the 3 pipes are open in how much time will the tank be filled?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #23134