SOLUTION: The spread of a flu virus in a community of 45,000 people is given by the function {{{f(t) = (45000)/(1+224e^(-899t))}}} where f(t) is the number of people in infected in week t.

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: The spread of a flu virus in a community of 45,000 people is given by the function {{{f(t) = (45000)/(1+224e^(-899t))}}} where f(t) is the number of people in infected in week t.       Log On


   



Question 1130047: The spread of a flu virus in a community of 45,000 people is given by the function f%28t%29+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29 where f(t) is the number of people in infected in week t.
When will half of the town be infected? (Show all work and give exact answers).

Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


I posted an answer to this problem previously, problem #1129948, answer #746566.

In that answer, I assumed the exponential in the function was supposed to be e^(-0.899t) instead of e^(-899t). Since the same problem is posted again, I will use the function as given.

We want to find the number of weeks t when half of the town (22500 people) will be infected:

22500+=+%2845000%29%2F%281%2B224e%5E%28-899t%29%29

1%2B224e%5E%28-899t%29+=+2

224e%5E%28-899t%29+=+1

e%5E%28-899t%29+=+1%2F224

-899t+=+ln%281%2F224%29

t+=+ln%281%2F224%29%2F-899

which is equal to 0.00601963 weeks, to several decimal places. That is equivalent to just over 1 hour -- which is not realistic.