Question

An acidophilus culture containing 150 bacteria doubles every 20 minutes. Write the exponential function then determine how much bacteria there are after 4 hours.

Answer 1

$20 \ min=\dfrac{1}{3}\ h$

Function that represents the number of bacteria is

$$N(t)=N(0)(2^{3t})$$

Given $N(0)=150, t=4\ h$

$$N(4)=150(2^{3(4)})=614400$$

There are 614400 bacteria after 4 hours