How many bacteria will there be at​ midnight?

Question

During a research​ experiment, it was found that the number of bacteria in a culture grew at a rate proportional to its size. At

99​:00

AM there were

4 comma 0004,000

bacteria present in the culture. At​ noon, the number of bacteria grew to

4 comma 8004,800.

How many bacteria will there be at​ midnight?

Answer 1

9953 at t=15 midnight

4000 at t=0

4800 at t=3

4800/4000= 1.2 = e^3r

r = (1/3)ln1.2

A = 4000e^(15(1/3)ln1.2)

= 9953.28