document.write( "Question 316631: If a boat travels downstream for one hour and travels twelve miles and returns upstream to the starting point and the trip requires four hours how fast is the current \n" ); document.write( "
Algebra.Com's Answer #226636 by ankor@dixie-net.com(22740)\"\" \"About 
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If a boat travels downstream for one hour and travels twelve miles and returns
\n" ); document.write( " upstream to the starting point and the trip requires four hours how fast is the current
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\n" ); document.write( "Let s = speed of boat in still water
\n" ); document.write( "Let c = speed of the current
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\n" ); document.write( "Write a distance equation for each trip:
\n" ); document.write( "1(s + c) = 12
\n" ); document.write( "4(s - c) = 12
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\n" ); document.write( "Simplify the second equation; divide by 4, subtract from the 1st equation
\n" ); document.write( "s + c =12
\n" ); document.write( "s - c = 3
\n" ); document.write( "-----------subtraction eliminates s, find c
\n" ); document.write( " 2c = 9
\n" ); document.write( "c = \"9%2F2\"
\n" ); document.write( "c = 4.5 mph is the current
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\n" ); document.write( "Check solution, find the speed of the boat
\n" ); document.write( "s + 4.5 = 12
\n" ); document.write( "s = 12 - 4.5
\n" ); document.write( "s = 7.5 mph speed of the boat
\n" ); document.write( "Check solution in the return equation
\n" ); document.write( "4(7.5 - 4.5) =
\n" ); document.write( "4(3) = 12 \n" ); document.write( "
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