For this case, we have that the total of people is 200.
If there are 20% of those people in the college, then we make a rule of three to determine the amount:
200 -----------> 100%
x ----------------> 20%
Where "x" represents the number of people who belong to the college.
![x = \frac {20 * 200} {100}\\x = 40](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%20%7B20%20%2A%20200%7D%20%7B100%7D%5C%5Cx%20%3D%2040)
So, we have 40 people belong to the school.
On the other hand, we use a rule of three to find the number of high school people:
200 ------------> 100%
y ----------------> 30%
Where "y" represents the number of people belonging to the high school.
![y = \frac {30 * 200} {100}\\y = 60](https://tex.z-dn.net/?f=y%20%3D%20%5Cfrac%20%7B30%20%2A%20200%7D%20%7B100%7D%5C%5Cy%20%3D%2060)
So, we have 60 people belong to high school.
Answer:
College: 40
High School: 60
60+40=100