N(t) = 650

1+649 e−0.5 t
.

(You may wish to sketch a graph of N(t) to help you understand this situation and answer the questions below.)

(a) How many people will have heard the rumor after 2 hours?

After 12 hours?

(b) When will half the people have heard the rumor? t =

(c) When is the rumor spreading fastest? t =

1 answer

Do you mean to divide?

N(t) = 650/(1+649e^-.5t)

What's the trouble? Straightforward evaluation of N or solving for t. That's just algebra.

If I have the function right, its graphs is

http://www.wolframalpha.com/input/?i=650%2F%281%2B649e^%28-.5t%29%29