Upstream and Downstream

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?

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distance = rate x time
or 
d = rt

However, the information given includes the rates and the total time of the trip.
So, solve the formula, d = rt for t (time).  You'll see why in a little bit!

d = rt {distance, rate, time formula}
t = d/r  {solved for t.....time equals distance divided by rate}

Now, apply that to what is given to you.

d = distance the point he got tired {which is the same distance upstream and downstream}

Remember, t = d/r  {the time is the distance divided by the rate}
d/2 + d/8 = 7  {the two times are d/2 and d/8....distance divided by rate}
4d + d = 56   {multiplied entire equation by 8 to eliminate fractions}
5d = 56   {combined like terms}
d = 11.2  {divided by 5}

distance upstream was 11.2
distance downstream was 11.2

Total distance = 22.4 miles

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