Hi there!
a.
To find the total amount of people that have ENTERED by t = 20, we must take the integral of the appropriate function.

Evaluate using a calculator:

b.
To solve, we can find the total amount of people that have entered of the interval and subtract the total amount of people that have left from this value.
In other terms:

We can evaluate using a calculator (math-9 on T1-84):


c.
If:

Then:

Evaluate at t = 20:


This means that at t = 20, there is a <u>NET DECREASE</u> of people at the movie theater of around 20.823 (21) people per hour.
d.
To find the maximum, we must use the first-derivative test.
Set S(t) - R(t) equal to 0:

Graph the function with a graphing calculator and set the function equal to y = 0:
According to the graph, the graph of the first derivative changes from POSITIVE to NEGATIVE at t ≈ 17.78 hours, so there is a MAXIMUM at this value.
<u>Thus, at t = 17.78 hours, the amount of people at the movie theater is a MAXIMUM.</u>
3 7 and 4 also 5 it makes sense
ALL OF THE ABOVE! All include human activity
The correct answer is - E.) to increase national sovereignty.
By cooperation on regional or global level the states do not, and can not really do anything about increasing the national sovereignty. The reason for that is that the national sovereignty is the matter of the state itself, its politics, policies, and handling of the situations in the country. The other countries with whom the state cooperates have nothing to do with it, nor it is their place to interfere in the national sovereignty of the other states, be it friendly states or not.