Posted by Anonymous on .
A bacteria culture has an initial population of 600. After 4 hours the population has grown to 1200. Assuming the culture grows at a rate proportional to the size of the population, find the function representing the population size after t hours and determine the size of the population after 8 hours.

maths plse help me.. 
Reiny,
Use
amount = a e^(kt) where a is the initial value, k is a constant, and t is in hours
1200 = 600 e^(k(4)
2 = e^(4k)
4k = ln 2
k = ln2 /4
amount = 600 e^((ln2/4)t)
when t=8
amount = 600 e^(2ln2)
= 2400
well, duh
Since the doubling period seems to be 4 hours
in 8 hours they would have doubled twice
600 > 1200 > 2400