9514 1404 393
Answer:
19.5 hours
Step-by-step explanation:
The number in the dish at time t (in hours) can be described by ...
n(t) = 100·2^(t/26)
We want to find t such that ...
n(t) = 168
100·2^(t/26) = 168
2^(t/26) = 1.68 . . . . . . divide by 100
(t/26)log(2) = log(1.68) . . . . . take logarithms
t = 26·log(1.68)/log(2) ≈ 19.459992 . . . . divide by the coefficient of t
t ≈ 19.5 . . . hours
It would be about 19.5 hours until there are 168 bacteria.
