document.write( "Question 64081: It took three hours to row a boat 18 km against the current. The return trip with the current took 1 1/2 hours. Find the speed of the rowboat in still water. \n" ); document.write( "
Algebra.Com's Answer #44732 by ptaylor(2198)\"\" \"About 
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Let x=boat's speed in still water and
\n" ); document.write( "Let y=speed of current\r
\n" ); document.write( "\n" ); document.write( "The boat's speed against the current (x-y) was 18km/3hr=6km/hr.
\n" ); document.write( "The boat's speed with the current (x+y) was 18km/1.5hr=12km/hr.
\n" ); document.write( "so we have:\r
\n" ); document.write( "\n" ); document.write( "(1) x-y=6km/hr
\n" ); document.write( "(2) x+y=12km/hr\r
\n" ); document.write( "\n" ); document.write( "adding the equations, we get:
\n" ); document.write( "2x=18km/hr divide both sides by 2 we have:
\n" ); document.write( "x=9km/hr speed of the boat in still water\r
\n" ); document.write( "\n" ); document.write( "substitute in (1) and we get:\r
\n" ); document.write( "\n" ); document.write( "9-y=6
\n" ); document.write( "-y=6-9
\n" ); document.write( "y=3km/hr speed of the current.\r
\n" ); document.write( "\n" ); document.write( "Hope this helps. Have a nice holiday season.----ptaylor\r
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