Question 891849:  A culture of bacteria obeys the law of uninhibited growth. If 140,000 are present initially and there are 609,000 after 6 hours. How long will it take to reach 1,000,000? 
 Answer by ankor@dixie-net.com(22740)      (Show Source): 
You can  put this solution on YOUR website! A culture of bacteria obeys the law of uninhibited growth. 
 If 140,000 are present initially and there are 609,000 after 6 hours. 
 How long will it take to reach 1,000,000? 
: 
An exponential growth formula 
Ao*e^(kt) = A, where 
Ao = initial amt 
t = time of growth 
k = exponential constant 
: 
Using 1000's bacteria; one million = 1000 
140*e^(6k) = 609 
e^(6k) = 609/140 
ln(e^6k) = ln(609/140) 
6k*ln(e) = 1.47 
ln of e = 1 
6k = 1.47 
k = 1.47/6 
k = .245 
: 
time required to have one million 
140*e^(.245t) = 1000 
ln(e^(.245k)) = ln(1000/140) 
.245t = 1.966 
t = 1.966/.245 
t = 8.02 ~ 8 hrs to have 1 million bacteria 
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