After 13 hours the population of bacteria in the culture is approximately 5,905,820, rounded to the nearest whole number.
we can use the formula for exponential growth
P = P0 * 2^(t/k)
Where:
P = population at time t
P0 = initial population = 74000
t = time = 13 hours
k = time for population to double = 3 hours
Plugging in the values:
P = 74000 * 2^(13/3)
P = 74000 * 2^4.33
P = 74000 * 79.83
P = 5905820