Question

The time it takes a swimmer (in hours) to go a distance of 5 miles up and down a river is given by f(x)=4/x-1 hours and g(x)=3/x+1 hours respectively, where x is the speed of the swimmer (in miles per hour) in still water and (2 < x < 20). Find the expression for the total time it takes to go 5 miles up the river and come back to the same point.