Question

A fisherman can row upstream at 2 mph and downstream at 8 mph. He started rowing upstream until he got tired and then rowed downstream to his starting point. How far did the fisherman row if the entire trip took 7 ​hours?

Answer 1

The fisherman rowed a total of 22.4 miles.

Explanation

Suppose, the distance from his starting point to the turn around point is $d$ mile.

Given that, upstream speed is 2 mph and downstream speed is 8 mph.

We know that,  $Time= \frac{Distance}{Speed}$

So, the time required to row $d$ miles upstream $= \frac{d}{2}$  hours and the time required to row $d$ miles downstream $= \frac{d}{8}$  hours.

As the entire trip took 7 ​hours, so the equation will be......

$\frac{d}{2}+\frac{d}{8}= 7\\ \\ 8(\frac{d}{2}+\frac{d}{8})= 8*7\\ \\ 4d+d= 56\\ \\ 5d= 56\\ \\ d= \frac{56}{5}=11.2$

So, the fisherman rowed a total of (11.2×2) miles = 22.4 miles