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Growth

by joyseychow » Thu Jul 16, 2009 1:40 am
The population of a bacteria culture doubles every 2 minutes. Approximately how many minutes will it take for the population to grow from 1,000 to 500,000 bacteria?

(A) 10
(B) 12
(C) 14
(D) 16
(E) 18

Is there is shortcut to growth questions? Thks.
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by kyosti » Thu Jul 16, 2009 1:50 am
1000*2^n = 500000
2^n = 500 (actually 2^n > 500)
n = 9 (while 2^9 = 512)

while the population doubles every 2 minutes, the total number of minutes is 9*2 = 18.

is this a correct answer?
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by shibal » Thu Jul 16, 2009 6:24 am
IMO B
min population
0 1000
2 2000
4 4000
6 8000
8 16000
10 32000
12 64000
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by joyseychow » Thu Aug 06, 2009 3:05 am
OA E
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