Problem 3
My toy boat has two speeds:
fast and
really fast. In fact, when going
really fast, the boat is travelling at twice the rate as it is when it is just going
fast. When my boat is set to
fast, it can travel 15 miles downstream in five hours less than the time it takes to return, but when it's set to
really fast, the time downstream is only one hour less than the time upstream. In miles per hour, what is the rate of the stream's current?
