Answer:
The correct answer is C. The rate of the boat in still water is of 35 miles per hour.
Step-by-step explanation:
As the boat makes a 120 mile trip downstream in 3 hours, and the return trip in 4 hours, we can say that it makes an entire 240 mile trip in 7 hours. As 240 / 7 = 35, that is the average speed the boat traveled in still water: the boat's rate in still water was of 35 miles per hour.
