Growth/Decay question!?

Question

Information began to spread one day in a city with a population of 100,000. Within 7 days, 10,000 heard about the information.
Assume that the rate of increase of the number who have heard the rumor is proportional to the number who have not yet heard it. How long will it be until half the population of the city has heard the rumor?

A=Ce^kt

THANKS SO MUCH! :)

Answer 1

0.9 = e^7k
-0.105 = 7k
k = -0.015

0.5 = e^-0.015t
-0.69 = -0.015t
t = 46 days

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