A fisherman rows up stream at 4mph and downstream at 6mph. He started rowing upstream until he got tired and then rowed downstream to his starting point. How far did the fisherman row in the whole trip in 7 hours?

Respuesta :

4 miles = 1 hour upstream
6 miles = 1 hour downstream

In seven hours: 4mi (7hr) = 28mi upstream + 6mi (7hr) = 42mi downstream
Added together: 28+42=70mi total.
distance up = distance down stream.distance = speed x timeso you have 2 equationsd= 4 td= 6 (7-t)where t is the time going up stream, and 7-t is the time going downstream.(because time up plus time down is 7)set the equations equal. solve for t.  use t to find d.