A family is canoeing downstream (with the current). Their speed relative to the banks of the river averages 2.75 mi/h. During the return trip, they paddle upstream (against the current), averaging 1.5 mi/h relative to the riverbank.
a. Write an equation for the rate of the canoe downstream.
b. Write an equation for the rate of the canoe upstream.
c. Solve the system to find the family's paddling speed in still water.
d. Find the speed of the current of the river.