document.write( "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? \n" ); document.write( "

Algebra.Com's Answer #22086 by Paul(988) $\"\"$ $\"About$

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Let the speed of theboat in still water be x
\n" ); document.write( " $\"60%2F%28x%2B3%29%2B60%2F%28x-3%29=9\"$
\n" ); document.write( "60[(x-3)+(x+3)]=9[(x+3)(x-3)]
\n" ); document.write( " $\"60%282x%29=9%28x%5E2-9%29\"$
\n" ); document.write( " $\"120x=9x%5E2-81\"$
\n" ); document.write( " $\"9x%5E2-120x-81=0\"$
\n" ); document.write( "SOlve that: you get x=13.9
\n" ); document.write( "Hence, the speed is 13.9mph in still wate.r
\n" ); document.write( "Paul.
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