document.write( "Question 27746: This is anouther problem that has given me a great deal of trouble. One pipe alone will fill a tank in 7.5 hours. a second pipe will fill it alone in 10 hours. If the second pipe were open for 8 hours. And then closed, how long would the frist pipe take to finish filling the tank?
\n" ); document.write( " The answer is 1.5 hours, but i don't know how to setup the problem. Thank you. \n" ); document.write( "

Algebra.Com's Answer #15115 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
One approach to this problem is first find the hourly rate of fill for each pipe. Let's call the first pipe A and the second pipe B.\r
\n" ); document.write( "\n" ); document.write( "If pipe A can fill the tank in 7.5 (15/2) hours, then it can fill 2/15 of the tank in 1 hour.
\n" ); document.write( "If pipe B can fill the tank in 10 hours, then it can fill 1/10 of the tank in 1 hour.\r
\n" ); document.write( "\n" ); document.write( "If pipe B were to be left open for 8 hours, then it would fill 8 X (1/10) of the tank.
\n" ); document.write( "So, after 8 hours, 4/5 of the tank would be filled leaving 1/5 of the tank to be filled by pipe A.\r
\n" ); document.write( "\n" ); document.write( "Now, pipe A can fill 2/15 of the tank in 1 hour, so how long would it take to fill the 1/5 of the tank?\r
\n" ); document.write( "\n" ); document.write( "Divide 1/5 by 2/15 $\"%281%2F5%29%2A%2815%2F2%29+=+3%2F2\"$ hours.\r
\n" ); document.write( "\n" ); document.write( "Pipe A would need 1.5 hours to finish filling the tank. \n" ); document.write( "

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