Applying the disinfectant once removes 90% of the bacteria, leaving 10% remaining.
Applying it a second time eliminates 90% of that remaining 10%, so you calculate 10 minus 90% of 10 to find the leftover bacteria after two applications.


This results in only 1% of the bacteria still being present, meaning that
99% of the original bacteria have been eradicated.
Response:
I am in the same situation regarding this homework, lol.
Answer:
See Explanation
Explanation:
The query lacks complete information because the value of s(t) is not provided;
Nonetheless, here is a useful guideline;
Let's proceed with the following assumption:

Required
Find the velocity at t = 8
To achieve this, first compute s(t) by inserting 8 for t in 




Next, calculate the velocity by taking s(t) and dividing it by t when t = 8
i.e.

Insert 8 for t

Insert 72 for s(8)


In summary: calculate s(8) first, then divide that number by 8 to obtain your answer