Answer: a) 800
b)
![y=100(2)^t](https://img.qammunity.org/2020/formulas/mathematics/college/8j8xptz3axx9xd0crlfv7i1fsefvrr0cmo.png)
Explanation:
The exponential growth function is represented by :-
, where A is initial value , b is the multiplicative rate of change and t is the time period.
Given : A bacteria culture starts with 100 bacteria and doubles in size every half hour.
i.e. A = 100 and b=2
Then, the exponential growth function to find the number of bacteris after t hours :_
![y=100(2)^t](https://img.qammunity.org/2020/formulas/mathematics/college/8j8xptz3axx9xd0crlfv7i1fsefvrr0cmo.png)
At x=3
![y=100(2)^3=800](https://img.qammunity.org/2020/formulas/mathematics/college/poa3q70u4mlphgy6xh9y65ty1zsf5qlqvf.png)
Hence, the there are 800 bacteria after 3 hours.