document.write( "Question 806074: A boat traveled 15 mph in still water. It traveled 20 mi upstream and back in a total of 3 hour. What is the speed of the current? \n" ); document.write( "
Algebra.Com's Answer #485645 by mananth(16946)\"\" \"About 
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boat speed = 15 mph
\n" ); document.write( "current speed = x mph
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\n" ); document.write( "against current = 15 - x
\n" ); document.write( "with current = 15 + x
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\n" ); document.write( "Total distance = 20 miles Total Time= 3.00 hours
\n" ); document.write( "Time upstream + time downstream = 3 hours
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\n" ); document.write( "20 /( 15 - x )+ 20 /( 15 + x )= 3
\n" ); document.write( "20 ( 15 + x )+ 20 ( 15 - x )= 3.00 ( 225 - 1 X^2 )
\n" ); document.write( "300 + 20 x + 300 -20 x = 675 - 3 X^2
\n" ); document.write( "600 - -675 = -3 X^2
\n" ); document.write( "-75 = -3 X^2
\n" ); document.write( "-3 X^2= -75
\n" ); document.write( "X^2 = 25
\n" ); document.write( "X = +/- 5
\n" ); document.write( "ignore negative
\n" ); document.write( "current speed = 5 mph \n" ); document.write( "
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