Algebra 2
posted by Casey .
The excursion boat on the river takes 2½ hours to make the trip to a point 12 miles upstream and to return. If the rate at which the boat travels in still water is 5 times the rate of the river current, what is the rate of the current?
Which of the following equations can be used to solve for c, the rate of the current?

rate of river  x mph
rate of boat  5x mph
12/x + 12/(5x) = 2.5
times 5x
60 + 12 = 12.5x
x = 5.76
change x to c