Question

A fisherman can row upstream at 4 mph and downstream at 6 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 6 hours? 

The distance the fisherman rowed is _______  mi. (Type an integer or a decimal.)

Answer 1

Suppose the fisherman goes x miles away from starting point.

Speed in upstream = 4 mph

Time taken to travel x miles in upstreaPm

= x/4 hours

Speed in downstream = 6 mph

Time taken to travel x miles in downstream

= x/6 hours

Time taken in entire trip = 6 hours

x/4 + x/6 = 6

Multiplying both sides by 12

3x + 2x =72

5x = 72

x =72/5

x = 14.4 miles

Total distance the fisherman rowed

= 14.4 + 14.4 = 28.8 miles

The distance the fisherman rowed = 28.8 miles