document.write( "Question 766346: a riverboat for tourists averages 12 mph in still water. It takes the boat 1hour and 4 minutes to go 6 miles upstream and return. find the rate of the current \n" ); document.write( "

Algebra.Com's Answer #466827 by mananth(16946) $\"\"$ $\"About$

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let speed of current be x\r
\n" ); document.write( "\n" ); document.write( "speed against current = 12-x\r
\n" ); document.write( "\n" ); document.write( "speed with current = 12+x\r
\n" ); document.write( "\n" ); document.write( "t=d/r\r
\n" ); document.write( "\n" ); document.write( "time upstream + time downstream = 1 hour 4 min\r
\n" ); document.write( "\n" ); document.write( " $\"6%2F%2812-x%29+%2B+6%2F%2812%2Bx%29=+16%2F15+\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "LCD = (12+x)(12-x)\r
\n" ); document.write( "\n" ); document.write( " $\"6%2812%2Bx%29%2B6%2812-x%29=+%2816%2F15%29%2812%2Bx%29%2812-x%29\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"72%2B6x%2B72-6x=%2816%2F15%29%28144-x%5E2%29\"$ \r
\n" ); document.write( "\n" ); document.write( "multiply by 15\r
\n" ); document.write( "\n" ); document.write( " $\"144%2A15+=+16%28144-x%5E2%29\"$
\n" ); document.write( "/16\r
\n" ); document.write( "\n" ); document.write( "9*15=144-x^2\r
\n" ); document.write( "\n" ); document.write( "x^2=144-135\r
\n" ); document.write( "\n" ); document.write( "x^2=9
\n" ); document.write( "x= +/- 3\r
\n" ); document.write( "\n" ); document.write( "so x =3 mph the speed of current\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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