SOLUTION: A stream is going 3 miles an hour. A boat travels upstream 12 miles and then returns to its original position downstream along the same route. If the speed of the boat in still wat

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Question 842540: A stream is going 3 miles an hour. A boat travels upstream 12 miles and then returns to its original position downstream along the same route. If the speed of the boat in still water is 9 miles per hour, what is the average speed for the whole trip there and back?
Answer by hamsanash1981@gmail.com(151) About Me  (Show Source):
You can put this solution on YOUR website!
upstream = 9-3 = 6
downstream = 9+3 = 12
average speed = (2*12*6)/(12+6)
=8 miles per hour