SOLUTION: The Hudson River flows at a rate of 3 miles per hour. A patrol boat travels 60 miles upriver, and returns in a total time of 9 hours. What is the speed of the boat in still water?

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Question 36034: The Hudson River flows at a rate of 3 miles per hour. A patrol boat travels 60 miles upriver, and returns in a total time of 9 hours. What is the speed of the boat in still water?
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Let the speed of theboat in still water be x
60%2F%28x%2B3%29%2B60%2F%28x-3%29=9
60[(x-3)+(x+3)]=9[(x+3)(x-3)]
60%282x%29=9%28x%5E2-9%29
120x=9x%5E2-81
9x%5E2-120x-81=0
SOlve that: you get x=13.9
Hence, the speed is 13.9mph in still wate.r
Paul.