Bactria math problem HMH unit 6

Question

Alexis is modeling the growth of bacteria for an experiment in science. She assumes that there are B bacteria in a Petri dish at 12:00 noon. In reality, each bacterium in the Petri dish subdivides into two new bacteria approximately every 20 minutes. However, for the purposes of the model, Alexis assumes that each bacterium subdivides into two new bacteria exactly every 20 minutes.

Answer 1

wouldn't it be

N(t)=B*2^3t ,,,,where t is measured in hours and/or fraction of hour from 12: noon

t=0, N=B, t=1/3 N=2B t=2/3 N=4B,...