Question 1083545
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Answer: <font color=red>Choice C) 6,693</font>
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Explanation:


During the first hour, the population declines by 9%
New population = (old population) - (9% of old population)
New population = (8700) - (9% of 8700)
New population = (8700) - (0.09*8700)
New population = 8700 - 783
New population = 7917


After the 9% decline, we go from 8700 bacteria to 7917 bacteria. 


But we add in an additional 50 new members: 
New population = (old population) + 50
New population = 7917 + 50
New population = 7967


At the end of the first hour, the population is 7967.


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During the second hour, the population declines by 9%
New population = (old population) - (9% of old population)
New population = (7967) - (9% of 7967)
New population = (7967) - (0.09*7967)
New population = 7967 - 717.03
New population = 7249.97
New population = 7250 ... rounding to the nearest whole number


After the 9% decline, we go from 7967 bacteria to 7250 bacteria. 


But we add in an additional 50 new members: 
New population = (old population) + 50
New population = 7250 + 50
New population = 7300


At the end of the second hour, the population is 7300.


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During the third hour, the population declines by 9%
New population = (old population) - (9% of old population)
New population = (7300) - (9% of 7300)
New population = (7300) - (0.09*7300)
New population = 7300 - 657
New population = 6643


After the 9% decline, we go from 7300 bacteria to 6643 bacteria. 


But we add in an additional 50 new members: 
New population = (old population) + 50
New population = 6643 + 50
New population = <font color=red>6693</font>


At the end of the third hour, the population is <font color=red>6693</font>.


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We are done because the third hour is over.
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