document.write( "Question 816215: A boat can travel 12 miles upstream in the same amount of time it takes to travel 18 miles downstream. If the current in the river is 3 miles per hour, find the speed of the boat in still water. \n" ); document.write( "
Algebra.Com's Answer #491412 by stanbon(75887)\"\" \"About 
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A boat can travel 12 miles upstream in the same amount of time it takes to travel 18 miles downstream. If the current in the river is 3 miles per hour, find the speed of the boat in still water.
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\n" ); document.write( "Upstream DATA:
\n" ); document.write( "distance = 12 miles ; rate = b-3 mph ; time = 12/(b-3) hrs.
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\n" ); document.write( "Downstream DATA:
\n" ); document.write( "distance = 18 miles ; rate = b+3 mph ; time = 18/(b+3) hrs.
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\n" ); document.write( "Equation::
\n" ); document.write( "time up = time down
\n" ); document.write( "12/(b-3) = 18/(b+3)
\n" ); document.write( "12b+36 = 18b-54
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\n" ); document.write( "6b = 90
\n" ); document.write( "b = 15 mph (speed of the boat in still water)
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\n" ); document.write( "Cheers
\n" ); document.write( "Stan H.\r
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