document.write( "Question 415603: Three pipes, A, B, and C are often used two at a time to fill a tank. When A and B are used together, the tank is filled in 5 minutes. When either A and C or B and C are used together, the tank is filled in 3 minutes. How long would it take each pipe alone to fill the tank? \n" ); document.write( "
Algebra.Com's Answer #291550 by ankor@dixie-net.com(22740)\"\" \"About 
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Three pipes, A, B, and C are often used two at a time to fill a tank.
\n" ); document.write( " When A and B are used together, the tank is filled in 5 minutes.
\n" ); document.write( " When either A and C or B and C are used together, the tank is filled in 3 minutes.
\n" ); document.write( " How long would it take each pipe alone to fill the tank?
\n" ); document.write( ":
\n" ); document.write( "Let the full tank = 1
\n" ); document.write( "\"5%2Fa\" + \"5%2Fb\" = 1
\n" ); document.write( "and
\n" ); document.write( "\"3%2Fa\" + \"3%2Fc\" = 1
\n" ); document.write( "or
\n" ); document.write( "\"3%2Fb\" + \"3%2Fc\" = 1
\n" ); document.write( ":
\n" ); document.write( "Use elimination with the 2nd and 3rd equations:
\n" ); document.write( "\"3%2Fa\" + \"3%2Fc\" = 1
\n" ); document.write( "\"3%2Fb\" + \"3%2Fc\" = 1
\n" ); document.write( "-----------------------------Subtraction eliminates 3/c
\n" ); document.write( "\"3%2Fa\" - \"3%2Fb\" = 0
\n" ); document.write( "therefore
\n" ); document.write( "\"3%2Fa\" = \"3%2Fb\"
\n" ); document.write( "therefore
\n" ); document.write( "a = b
\n" ); document.write( ":
\n" ); document.write( "using the 1st equation, replace b with a
\n" ); document.write( "\"5%2Fa\" + \"5%2Fa\" = 1
\n" ); document.write( "\"10%2Fa\" = 1
\n" ); document.write( "a = 10 hrs alone
\n" ); document.write( "then
\n" ); document.write( "b = 10 hrs alone
\n" ); document.write( ":
\n" ); document.write( "Find c:
\n" ); document.write( "\"3%2F10\" + \"3%2Fc\" = 1
\n" ); document.write( "Multiply by 10c
\n" ); document.write( "3c + 10(3) = 10c
\n" ); document.write( "30 = 10c - 3c
\n" ); document.write( "30 = 7c
\n" ); document.write( "c = \"30%2F7\"
\n" ); document.write( "c = 4\"2%2F7\" hrs alone
\n" ); document.write( ":
\n" ); document.write( "Summarize: A = 10 hrs, B = 10 hrs, C = 4\"2%2F7\" hrs
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "You can check this in the original equations using; C=4.2857
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