The answer is 30720
A = P * rⁿ
A - the final population
r - the growth rate
P - the initial number of bacteria
n - the number of hours
We know:
A = ?
r = 2 (it doubles)
P = 15
n = 12
After 11 hours
A(11) = 15 * 2¹²
A(11) = 15 * 2048
A(11) = 30720
After 12 hours
A(12) = 15 * 2¹²
A(12) = 15 * 4096
A(12) = 61440
How many bacteria are grown during the 12th hour?
A(12) - A(11) = 61440 - 30720 = 30720
