Speed word problem

Question

The speed of a stream is 3mph. A boat travels 10 miles upstream in the same time it takes to travel 16 miles downstream. What is the speed of the boat in still water?

Answer 1

Let v = speed of boat in still water.

Relative speed upstream = v - 3

Relative speed downstream = v + 3

 time upstream = 10/ (v-3)

 time downstream  = 16/ (v + 3)

 time upstream = time downstream ⇒

 10/ (v-3) = 16/ (v + 3)

 

Solve this equation.

v = 13