Two pipes A and B can separately empty a cistern in 45…

Two pipes A and B can separately empty a cistern in 45 min and 30 min respectively. There is a third pipe in the top of the cistern to fill it. If all the three pipes are simultaneously opened, then the cistern is full in 90 min. In how much time, the third pipe alone can fill the cistern?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #43072