document.write( "Question 790533: A tank can be filled by two pipes separately in 10 and 15 minutes respectively. When a third pipe is used simultaneously with the first two pipes, the tank can be filled in 4 minutes. How long would it take for the third pipe alone to fill the tank? \n" ); document.write( "
Algebra.Com's Answer #479173 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
A tank can be filled by two pipes separately in 10 and 15 minutes respectively. When a third pipe is used simultaneously with the first two pipes, the tank can be filled in 4 minutes. How long would it take for the third pipe alone to fill the tank?
\n" ); document.write( "--------
\n" ); document.write( "1st pipe rate: 1/10 job/minute
\n" ); document.write( "2nd pipe rate: 1/15 job/minute
\n" ); document.write( "3rd pipe rate: 1/x job/min
\n" ); document.write( "Together rate: 1/4 job/min
\n" ); document.write( "-----
\n" ); document.write( "Equation:
\n" ); document.write( "rate + rate + rate = together rate::
\n" ); document.write( "1/10 + 1/15 + 1/x = 1/4
\n" ); document.write( "------------
\n" ); document.write( "6x + 4x + 60 = 15x
\n" ); document.write( "5x = 60
\n" ); document.write( "x = 12 minutes (time for the 3rd pipe to fill the tank)
\n" ); document.write( "============
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "============= \n" ); document.write( "
\n" );