document.write( "Question 1163560: a new type of pump can drain a pool in 6 hours. an older pump can drain the pool in 12 hours. how long will it take both pumps working together to drain the pool? \n" ); document.write( "

Algebra.Com's Answer #787691 by ikleyn(52835) $\"\"$ $\"About$

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document.write( "It can be solved mentally, without using equations.\r\n" );
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document.write( "The new pump works as productive as two old pumps.\r\n" );
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document.write( "So, the old pump and the new pump, working together, are equivalent to three old pumps.\r\n" );
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document.write( "One old pumps completes the job in 12 hours.   \r\n" );
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document.write( "Hence, the two pumps, been equivalent to 3 old pumps, will complete the job in 12/3 = 4 hours.      ANSWER\r\n" );
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