document.write( "Question 98649: A hose can fill a swimming pool in 6 hours. Another hose needs 3 more hours to fill the pool than the two hoses combined. How long would it take the second hose to fill the pool? \n" ); document.write( "
Algebra.Com's Answer #71791 by malakumar_kos@yahoo.com(315)\"\" \"About 
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\n" ); document.write( " A hose can fill a swimming pool in 6 hours. Another hose needs 3 more hours to fill the pool than the two hoses combined. How long would it take the second hose to fill the pool?\r
\n" ); document.write( "\n" ); document.write( " let the two horses be A & B \r
\n" ); document.write( "\n" ); document.write( " time taken by horse A = 6 hrs\r
\n" ); document.write( "\n" ); document.write( " time taken by horse B = y hrs\r
\n" ); document.write( "\n" ); document.write( " time taken by A & B together = 6+x hrs \r
\n" ); document.write( "\n" ); document.write( " y = 6+x+3
\n" ); document.write( " y = x+9...........(1)\r
\n" ); document.write( "\n" ); document.write( " Qu'ty of pool filled by A in 1 hr = 1/6\r
\n" ); document.write( "\n" ); document.write( " Qu'ty of pool filled by B in 1 hr = 1/y\r
\n" ); document.write( "\n" ); document.write( " Qu'ty of pool filled by A & B in 1 hr = 1/(6+x) \r
\n" ); document.write( "\n" ); document.write( " 1/(6+x) = 1/6+1/y\r
\n" ); document.write( "\n" ); document.write( " 1/(6+x) = y+6/6y\r
\n" ); document.write( "\n" ); document.write( " 6y = (6+y)(6+x)\r
\n" ); document.write( "\n" ); document.write( " 6y = 36+6x+6y+xy\r
\n" ); document.write( "\n" ); document.write( " -6x-xy = 36.......(2)\r
\n" ); document.write( "\n" ); document.write( " substituting for y in (2) we get -6x - x(x+9)= 36\r
\n" ); document.write( "\n" ); document.write( " -6x -x^2-9x = 36\r
\n" ); document.write( "\n" ); document.write( " -x^2-15x-36 = 0\r
\n" ); document.write( "\n" ); document.write( " x^2+15x+36 =0
\n" ); document.write( " Factors of 36 are 12 &3 x^2+12x+3x+36 = 0\r
\n" ); document.write( "\n" ); document.write( " x(x+12)+3(x+12)= 0\r
\n" ); document.write( "\n" ); document.write( " (x+12)(x+3) = 0\r
\n" ); document.write( "\n" ); document.write( " x+12 = 0 or x = -12\r
\n" ); document.write( "\n" ); document.write( " x+3 = 0 or x = -3\r
\n" ); document.write( "\n" ); document.write( " time taken by horse B to fill the pool = y = x+9
\n" ); document.write( " if x = -3 then y = -3+9 = 6 hrs
\n" ); document.write( " if x = -12 then y = -12+9 = -3 \r
\n" ); document.write( "\n" ); document.write( " -3 hrs cannot be considered so x= 6 hrs is the required value\r
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