document.write( "Question 1159185: The doubling period of a bacterial population is 15 minutes. At time t= 120
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Algebra.Com's Answer #782264 by ikleyn(52832) $\"\"$ $\"About$

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document.write( "120 minutes comprise 8 times 15-minute periods.\r\n" );
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document.write( "So, 120 minutes comprise 120/15 = 8 doubling periods.\r\n" );
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document.write( "When we go one doubling period back, from 120 minutes to 105 minutes, we should divide the current population size by the factor of 2.\r\n" );
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document.write( "When we go 8 doubling periods back, from 120 minutes to the very beginning, we should divide the population of 60000 by , \r\n" );
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document.write( "which gives the initial population  =  = 234.375 = 234 (rounded).\r\n" );
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document.write( "From 120 minutes to 5 full hours, we have 3 hours = 3*4 = 12 doubling periods.\r\n" );
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document.write( "Therefore, the size of the bacterial population after 5 hours is   = 245760000.\r\n" );
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