The bacteria in a certain culture double every 7.3 hours. the culture has 6000 bacteria at the start. how many bacteria will the culture contain after 4 years

The bacteria in a certain culture double every 7.1 hours.
The culture has 6,500 bacteria at the start. How much after 4 hrs
:
Using the formula: A = Ao*2^(t/d) where
A = amt after t time

Ao = initial amt (t=0)
t = time of action
d = doubling time of the bacteria
;
A = 6500*2^(4/7.1)
A = 6500 * 1.4777
A = 9605 bacteria after 4 hrs