document.write( "Question 208013: Julie and Eric row their boat (at a constant speed) 45 miles downstream for 5 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours. Find the rate of the current. please help \n" ); document.write( "
Algebra.Com's Answer #157407 by ankor@dixie-net.com(22740)\"\" \"About 
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Julie and Eric row their boat (at a constant speed) 45 miles downstream for 5
\n" ); document.write( " hours, helped by the current. Rowing at the same rate, the trip back against
\n" ); document.write( " the current takes 9 hours. Find the rate of the current.
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\n" ); document.write( "Let s = speed of the boat in still water
\n" ); document.write( "Let c = rate of the current
\n" ); document.write( "Then
\n" ); document.write( "(s-c) = speed upstream
\n" ); document.write( "(s+c) = speed downstream
\n" ); document.write( ":
\n" ); document.write( "Write two distance equation, use elimination
\n" ); document.write( "5(s+c) = 45
\n" ); document.write( "9(s-c) = 45
\n" ); document.write( "Simplify, divide 1st equation by 5, 2nd equation by 9; results
\n" ); document.write( "s + c = 9
\n" ); document.write( "s - c = 5
\n" ); document.write( "-----------Subtraction eliminates s, find c
\n" ); document.write( "2c = 4
\n" ); document.write( "c = 2 mph is the current
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solution:
\n" ); document.write( "Find s:
\n" ); document.write( "s + 2 = 9
\n" ); document.write( "s = 9-2
\n" ); document.write( "s = 7 mph in still water
\n" ); document.write( ":
\n" ); document.write( "Check solution in original upstream equation:
\n" ); document.write( "9(7-2) = 45
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