document.write( "Question 863240: A man rows a boat 630 feet upstream against a constant current in 14 minutes. He then rows 385 feet downstream (with the same current) in 7 minutes. Find the speed of the current and the equivalent rate at which he can row in still water. \n" ); document.write( "
Algebra.Com's Answer #520337 by ankor@dixie-net.com(22740)\"\" \"About 
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A man rows a boat 630 feet upstream against a constant current in 14 minutes.
\n" ); document.write( " He then rows 385 feet downstream (with the same current) in 7 minutes. Find the speed of the current and the equivalent rate at which he can row in still water.
\n" ); document.write( ":
\n" ); document.write( "Let s = rowing speed in still water (ft/min)
\n" ); document.write( "Let c = rate of the current (ft/min)
\n" ); document.write( ":
\n" ); document.write( "Write a distance equation for each way. dist = speed * time
\n" ); document.write( "14(s-c) = 630
\n" ); document.write( "7(s+c) = 385
\n" ); document.write( ":
\n" ); document.write( "We can simplify both equations, divide the 1st by 14, the 2nd by 7, result:
\n" ); document.write( "s - c = 45
\n" ); document.write( "s + c = 55
\n" ); document.write( "------------Adding eliminates c find s
\n" ); document.write( "2s = 100
\n" ); document.write( "s = 100/2
\n" ); document.write( "s = 50 ft/min is his rowing speed
\n" ); document.write( "then
\n" ); document.write( "50 + c = 55
\n" ); document.write( "c = 5 ft/min is the current
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check that in the 1st original equation
\n" ); document.write( "14(50 - 5) = 630
\n" ); document.write( "14(45) = 630
\n" ); document.write( ":
\n" ); document.write( "You can check it in the 2nd original equation \n" ); document.write( "
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