document.write( "Question 167202: Julie and Eric row their boat( at a constant speed) 45 miles downstream for 5 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours. Find the rate of the current. \n" ); document.write( "

Algebra.Com's Answer #123145 by Mathtut(3670) $\"\"$ $\"About$

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d=r*t in this instance $\"r%5Bd%5D=r%5Bb%5D%2Br%5Bc%5D\"$ $\"r%5Bu%5D=r%5Bb%5D-r%5Bc%5D\"$ where $\"r%5Bd%5D\"$ rate downstream and $\"r%5Bu%5D\"$ rate upstream $\"r%5Bb%5D\"$ rate of the boat $\"r%5Bc%5D\"$ is the rate of the current $\"r%5Bd%5D=45%2F5=9\"$ \r
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\n" ); document.write( "\n" ); document.write( "we know that $\"45=r%5Bd%5D%285%29\"$ ----> $\"45=%28r%5Bb%5D%2Br%5Bc%5D%295\"$
\n" ); document.write( ": $\"45=r%5Bu%5D%289%29\"$ ----> $\"45=%28r%5Bb%5D-r%5Bc%5D%299\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"45=5r%5Bb%5D%2B5r%5Bc%5D\"$
\n" ); document.write( " $\"45=9r%5Bb%5D-9r%5Bc%5D\"$ \r
\n" ); document.write( "\n" ); document.write( "multiply top by 9 and bottom by 5 to eliminate the $\"r%5Bc%5D\"$ terms\r
\n" ); document.write( "\n" ); document.write( " $\"90r%5Bb%5D=630\"$ $\"highlight%28r%5Bb%5D=7%29\"$ \r
\n" ); document.write( "\n" ); document.write( "so $\"highlight%28r%5Bc%5D=9-7=2%29\"$ \n" ); document.write( "

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