For this case we have a function of the form:
 [tex]y = A * (b) ^ t
[/tex]
 Where,
 A: it is the initial amount of bacteria
 b: growth rate
 t: it's time
 By the time the bacteria are double we have that y = 2A
 Substituting values:
 [tex]2A = A * (1,083) ^ t
[/tex]
 From here, we clear t:
 [tex](1,083) ^ t = 2
log1.083 ((1.083) ^ t) = 2
t = log1.083 (2)
t = 8.7 hours[/tex]
 Answer:
 it takes for the size of the sample to double about:
 [tex]t = 8.7 hours[/tex]