Of 200 people, how many people are in junior and senior high school?

college : 20%

high
school : 30%

junior and senior high school :

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.

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.

So, we have 60 people belong to high school.

College: 40

High School: 60

60+40=100

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x