A fisherman can row upstream at 1 mph and downstream at 4 mph. He started rowing upstream until he got tired and then rowed downstream to his starting point. How far did the fisherman row off the entire trip took 5 hours?
it took him 4 hours to get upstream which is 4 miles and since he can do 4 miles per hour down stream it only took him an hour to get back to the starting point which is 5 hours in total.