SOLUTION: If a boat in a 4 mph current can travel 76 miles downstream in the same time it takes to travel 20 miles upstream, what is the speed of the boat in still water

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Question 450104: If a boat in a 4 mph current can travel 76 miles downstream in the same time it takes to travel 20 miles upstream, what is the speed of the boat in still water
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

 

Hi,

Let x represent speed of boat in still water

Question states***Times up and downstream the same: t = D/r

 76/(x+4) = 20/(x-4)   Cross Multiplying 

  76(x-4) = 20(x+4)

     56x = 80 + 304

     56x = 384

       x = 6.857 mph, the speed of boat in still water