Answer:
About 53022 bacteria present.
Explanation:
We can use the continuous growth formula:

Where k is some constant.
With an initial population of 5000, it grew to 6500 after two hours.
In other words, P = 6500 when A = 5000 and t = 2:

Solve for k:

Therefore, our equation is:

After 18 hours, t = 18. Hence:

Therefore, after 18 hours, there will be about 53022 bacteria present.