Question

The number of hours, t, that bacteria spread 10-fold can be modeled by the equation B(t) = B0(10)4t. There are 50 bacteria present initially and a biologist wishes to find out how many hours will elapse until there are 10,000 bacteria present. What is the exact value for the number of hours elapsed, t, in the equation 10,000 = 50(10)4t?

Answer 1

t = (log200)/4 hours

Explanation:

10,000 = 50(10)^(4t)

Divide both sides by 50

200 = 10^(4t)

Take the log of both sides

log200 = 4t

Divide both sides by 4

(log200)/4 = t

t = (log200)/4 (exact answer)

t ≈ 0.575257498915995 (numeric approximation)