document.write( "Question 1010003: Stephanie took her kayak to the kaweak river, which flows downstream at a rate of 2 kilometers per hours. She paddled 15 km upstream, and then paddle downstream to her starting point. If this round trip took a total of 4 hours, find the speed that Stephanie can paddle in still water. \n" ); document.write( "
Algebra.Com's Answer #625482 by stanbon(75887)\"\" \"About 
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Stephanie took her kayak to the kaweak river, which flows downstream at a rate of 2 kilometers per hours. She paddled 15 km upstream, and then paddle downstream to her starting point. If this round trip took a total of 4 hours, find the speed that Stephanie can paddle in still water.
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\n" ); document.write( "Upstream DATA::
\n" ); document.write( "distance = 15 km ; rate = b-2 mph ; time = 15/(b-2) hrs
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\n" ); document.write( "Downstream DATA:
\n" ); document.write( "distance = 15 km ; rate = b+2 mph ; time = 15/(b+2) hrs
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\n" ); document.write( "Equation:
\n" ); document.write( "time + time = 4 hrs
\n" ); document.write( "15/(b-2) + 15/(b+2) = 4
\n" ); document.write( "15(b+2) + 15(b-2) = 4(b^2-4)
\n" ); document.write( "30b = 4b^2 - 16
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\n" ); document.write( "2b^2 - 15b - 8 = 0
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\n" ); document.write( "Factor::
\n" ); document.write( "2b^2 - 16b+ b - 8 = 0
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\n" ); document.write( "2b(b-8) + b-8 = 0
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\n" ); document.write( "(b-8)(2b+1) = 0
\n" ); document.write( "Positive solution::
\n" ); document.write( "boat speed = 8 km/hr
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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