document.write( "Question 60961: If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are? I've got a solution and the answer is correct, but I don't think I worked it out right. \n" ); document.write( "
Algebra.Com's Answer #41939 by ankor@dixie-net.com(22740)\"\" \"About 
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If a boat goes downstream 72 miles in 3 hours and upstream 60 miles in 6 hours, the rate of the river and the rate of the boat in still water respectively are?
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\n" ); document.write( "Let x = speed of boat in still water, Let y = speed of river
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\n" ); document.write( "Make two equations; time * speed = distance:
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\n" ); document.write( "Downstream equation:
\n" ); document.write( "3(x + y) = 72\r
\n" ); document.write( "\n" ); document.write( "Simplify, divide eq by 3
\n" ); document.write( "x + y = 24
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\n" ); document.write( "Upstream equation:
\n" ); document.write( "6(x - y) = 60
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\n" ); document.write( "Simplify divide by 6
\n" ); document.write( "x - y = 10
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\n" ); document.write( "Use elimination method on the these two equations:
\n" ); document.write( "x + y = 24
\n" ); document.write( "x - y = 10
\n" ); document.write( "------------ add
\n" ); document.write( "2x + 0 = 34
\n" ); document.write( "x = 34/2
\n" ); document.write( "x = 17 mph, speed of the boat in still water:
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\n" ); document.write( "Find river speed:
\n" ); document.write( "17 - y = 10
\n" ); document.write( "y = 7 mph is the rive speed
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\n" ); document.write( "Check:
\n" ); document.write( "3(17+7) = 72
\n" ); document.write( "6(17-7) = 60
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\n" ); document.write( "Make sense to you? Any questions?
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