document.write( "Question 1141775: A boat traveled downstream a distance of 36 mi and then came right back. If the speed of the current was 12 mph and the total trip took 4 hour find the average speed of the boat relative to the water. \n" ); document.write( "

Algebra.Com's Answer #762401 by josgarithmetic(39618) $\"\"$ $\"About$

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r, unknown speed of boat without current
\n" ); document.write( "C=12, speed of current
\n" ); document.write( "T=4, total trip time
\n" ); document.write( "D=36, distance traveled in each direction\r
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document.write( "                SPEED        TIMES            DISTANCE\r\n" );
document.write( "\r\n" );
document.write( "DOWNSTREAM        r+C         D/(r+C)             D\r\n" );
document.write( "\r\n" );
document.write( "UPSTREAM         r-C          D/(r-C)            D\r\n" );
document.write( "\r\n" );
document.write( "TOTALS                       T\r\n" );
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\n" ); document.write( " $\"D%2F%28r%2BC%29%2BD%2F%28r-C%29=T\"$
\n" ); document.write( "Solve for r, and then substitute the given values.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Algebra steps may lead to: $\"r%5E2-%282D%2FT%29r-C%5E2=0\"$ \r
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\n" ); document.write( "\n" ); document.write( "If substitute the given values here, then $\"r%5E2-18r-144=0\"$ .
\n" ); document.write( "You may find this factorable as $\"%28r-24%29%28r%2B6%29=0\"$ .\r
\n" ); document.write( "\n" ); document.write( " $\"highlight%28r=24%29\"$ \n" ); document.write( "

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