Answer:
The rate of the current is 5.5 miles per hour
Step-by-step explanation:
Relative Speeds
The boat takes 2 hours to travel 15 miles upriver against the current. The speed is 15/2 = 7.5 miles per hour.
Since the boat in still water can travel at 13 miles per hour, it means the current subtracts its speed from the speed of the boat:
Vcurrent = 13 mi/h - 7.5 mi/h
Vcurrent = 5.5 mi/h
The rate of the current is 5.5 miles per hour
