document.write( "Question 203118: 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? \n" ); document.write( "
Algebra.Com's Answer #153413 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,
\n" ); document.write( " 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 = the rate of the boat
\n" ); document.write( "Let y = the rate of the current
\n" ); document.write( "then
\n" ); document.write( "(x+y) = boat speed downstream
\n" ); document.write( "(x-y) = boat speed upstream
\n" ); document.write( ":
\n" ); document.write( "Write two distance equations: dist = time * speed
\n" ); document.write( ":
\n" ); document.write( "3(x + y) = 72
\n" ); document.write( "6(x - y) = 60
\n" ); document.write( ":
\n" ); document.write( "Simplify both equations, divide the 1st by 3, and the 2nd by 6: results:
\n" ); document.write( "x + y = 24
\n" ); document.write( "x - y = 10
\n" ); document.write( "-------------addition eliminates y, find x:
\n" ); document.write( "2x = 34
\n" ); document.write( "x = \"34%2F2\"
\n" ); document.write( "x = 17 mph boat speed in still water
\n" ); document.write( "and
\n" ); document.write( "17 + y = 24
\n" ); document.write( "y = 24 - 17
\n" ); document.write( "y = 7 mph is the current speed
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solution in the 1st equation
\n" ); document.write( "3(17 + 7) = 24
\n" ); document.write( "2(24) = 72 \n" ); document.write( "
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