document.write( "Question 48227: Find the speed of a motor boat in still water and the speed of a river current, if it takes 3 hrs. to travel a distance of 45m. upstream and 2 hrs. to travel 50 m. downstream. \n" ); document.write( "
Algebra.Com's Answer #31924 by Paul(988)\"\" \"About 
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Let x be the boat's speed and let y be the speed of the current
\n" ); document.write( "EQUATION 1:
\n" ); document.write( "upstream = -
\n" ); document.write( "-->3x-3y=45
\n" ); document.write( "EQUATION 2:
\n" ); document.write( "Downstream = +
\n" ); document.write( "-->2x+2y=50
\n" ); document.write( "Multiply E1 by 2 and E2 by 3
\n" ); document.write( "6x-6y=90
\n" ); document.write( "6x+6y=150
\n" ); document.write( "add:
\n" ); document.write( "12x=240
\n" ); document.write( "x=20\r
\n" ); document.write( "\n" ); document.write( "3(20)-3y=45
\n" ); document.write( "-3y=-15
\n" ); document.write( "y=5
\n" ); document.write( "Hence, the speed of the boat is 20mph and the speed of the current is 5mph.
\n" ); document.write( "Paul. \n" ); document.write( "
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