document.write( "Question 732913: PumP A, working alone, can fill a tank in 3 hours, and pump B can fill tthe same tank in 2 hours. If the tank is empty to start and pump a is switched on for 1 hour, after which pump b is also switched on and the two work together, how many minutes will pump b have been working by the time the pool is filled? \n" ); document.write( "

Algebra.Com's Answer #852830 by ikleyn(53431) $\"\"$ $\"About$

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\n" ); document.write( "Pump A, working alone, can fill a tank in 3 hours, and pump B can fill the same tank in 2 hours.
\n" ); document.write( "If the tank is empty to start and pump A is switched on for 1 hour, after which pump B is also switched on
\n" ); document.write( "and the two work together, how many minutes will pump B have been working by the time the pool is filled?
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\n" ); document.write( "\n" ); document.write( " On the way, the tank was transformed into the pool, \r
\n" ); document.write( "\n" ); document.write( " but I will consider this transformation as playing words.\r
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document.write( "So, we know that pump A fills the tank in 3 hours = 180 minutes, working alone,\r\n" );
document.write( "while pump B fills the tank in 2 hours = 120 minutes working alone.\r\n" );
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document.write( "When pump A worked alone during 1 hour, it filled 1/3 of the tank volume; \r\n" );
document.write( "so, 2/3 of the volume remained to fill.\r\n" );
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document.write( "Pump A fills  1/180  of the tank volume per minute;\r\n" );
document.write( "pump B fills  1/120  of the tank volume per minute.\r\n" );
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document.write( "Working together, two pumps fill\r\n" );
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document.write( "     +  =  +  =  = \r\n" );
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document.write( "of the tank volume per minute.\r\n" );
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document.write( "And these two pumps should fill 2/3 of the tank volume.\r\n" );
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document.write( "It will take for them\r\n" );
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document.write( "     =  = 2*24 = 48 minutes.\r\n" );
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document.write( "ANSWER.  Pump B will work 48 minutes together with pump A to fill the tank. \r\n" );
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\n" ); document.write( "\n" ); document.write( "Thus the problem is just solved completely.\r
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\n" ); document.write( "\n" ); document.write( "As you see from my post, my solution even does not require using equation:
\n" ); document.write( "it only requires manipulating with fractions.\r
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