document.write( "Question 398162: A boat travels 27 miles downstream in 3 hours, and when traveling upstream it takes twice as much time to travel 2/3 of that distance. Find the rate of the boat in still water and the rate of the current. \n" ); document.write( "
Algebra.Com's Answer #282169 by ankor@dixie-net.com(22740)\"\" \"About 
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A boat travels 27 miles downstream in 3 hours, and when traveling upstream
\n" ); document.write( " it takes twice as much time to travel 2/3 of that distance.
\n" ); document.write( " Find the rate of the boat in still water and the rate of the current.
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\n" ); document.write( "Find the upstream distance: \"2%2F3\"*27 = 18 miles
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\n" ); document.write( "Let s = boat speed in still water
\n" ); document.write( "Let c = current speed
\n" ); document.write( "then
\n" ); document.write( "(s-c) = effective speed upstream
\n" ); document.write( "and
\n" ); document.write( "(s+c) = effective speed downstream
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\n" ); document.write( "Write a distance equation for each way
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\n" ); document.write( "3(s+c) = 27
\n" ); document.write( "6(s-c) = 18
\n" ); document.write( "Simplify both equations, divide the 1st by 3, and the 2nd by 6, results:
\n" ); document.write( "s + c = 9
\n" ); document.write( "s - c = 3
\n" ); document.write( "------------addition eliminates c, find s
\n" ); document.write( "2s = 12
\n" ); document.write( "s = 6 mph is the boat speed in still water
\n" ); document.write( "and
\n" ); document.write( "6 + c = 9
\n" ); document.write( "c = 3 mph is the current speed
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\n" ); document.write( "Check solutions by finding the distance
\n" ); document.write( "3(6+3) = 27
\n" ); document.write( "6(6-3) = 18 \n" ); document.write( "
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