Learning Goal: I’m working on a writing mathematics question and need guidance t

Learning Goal: I’m working on a writing mathematics question and need guidance to help me learn.
Pump P can fill an empty water tank in 7½ hours while pump Q can fill the same tank in 11¼ hours. On a certain day, when the tank was empty, both pumps were opened for 2½ hours.
a. Determine the fraction of the tank that was still empty at the end of the 2½ hours.(4 marks)
b. Pump P was later opened alone to completely fill the tank. Determine the time it took pump P to fill the remaining fraction of the tank.(2 marks)
c. The two pumps P and Q are operated by different proprietors. Water from the full tank was sold for Ksh 15 750. The money was shared between the two proprietors in the ratio of the quantity of water supplied by each.
Determine the amount of money received by the proprietor of pump P.