Question 974635:  At  the start of an experiment, Lucy had 4000 bacteria cells in a culture. The number of bacteria double each hour.
 
The number of bacteria after x hours can be found using formula B =4000(2x). 
 
How many hours have passed if 2,048,000 bacteria cells are present?
 
A) 9 hours
 
B) 10 hours
 
C) 8 hours
 
D) 7 hours 
 Answer by Alan3354(69443)      (Show Source): 
You can  put this solution on YOUR website! At  the start of an experiment, Lucy had 4000 bacteria cells in a culture. The number of bacteria double each hour.
 
The number of bacteria after x hours can be found using formula B =4000(2x). 
How many hours have passed if 2,048,000 bacteria cells are present?  
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I think you mean B =4000*2^x  Use ^ (Shift 6) for exponents. 
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B =4000*2^x = 2048000 
2^x = 512 
2^x = 2^9 
x = 9 hours 
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If you don't recognize that 512 = 2^9: 
2^x = 512 
x*log(2) = log(512) 
x = log(512)/log(2) 
x = 9 
 
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