Question

A boat takes 2 hours to travel 15 miles upriver against the current. If the rate of the boat in still water is 13 miles per hour what is the rate of the current?

Answer 1

The rate of the current is 5.5 miles per hour

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