For this case we have an equation of the form:
y = A (b) ^ (t / n)
Where,
A: initial amount
b: growth rate
t: time
n: number of time periods
Substituting values we have:
y = 5 * (4) ^ (90/15)
y = 20480
Answer:
will be presents after 90 minutes about:
y = 20480 bacteria
