IBPS PO RRB PO Prelims 6 Aug 2023 Shift 2 Paper

Pipe P alone can fill the tank in 18 hours and pipe Q alone can fill the tank in 12 hours. Both pipes opened for 7 hours. The fraction of the tank remained after 7 hours is equal to the fraction of the tank filled by pipe R in one hour. In what time the tank gets filled when all three pipes are opened simultaneously?