1. Magnet School
Jacquline Price

2. Strategy: Identify Subproblems

3. Problem: Magnet School
A magnet school program was set up to bring in students from all over the city. With the first 112 students, the magnet program had 50% from the south side of town, 12.5% from the north side, and 37.5% from the east side. If 6 more students from the north side and 2 students from the west side enrolled in the program, what would be the percentage of students from the north side in the program now?

4. 7th Grade/Math

5. TEKS §111.23. Mathematics, Grade 7 (b) Knowledge and Skills
(b) Knowledge and Skills
(2) Number, operation, and quantitative reasoning. The student adds, subtracts, multiplies, or divides to solve problems and justify solutions. The student is expected to:
(B) use addition, subtraction, multiplication, and division to solve problems involving fractions and decimals;
(F) select and use appropriate operations to solve problems and justify the selections; and
(G) determine the reasonableness of a solution to a problem.

6. Resources/Materials:
Paper
Pencil
Calculator

7. Known Of the first 112 students enrolled in the program:
50% are from the south side of town
12.5% are from the north side of town
37.5% are from the east side of town
Additional students enrolled in the program:
6 more came from the north side of town
2 came from the west side of town

8. Unknown
What would be the percentage of students enrolled from the north side of the city after additional students enrolled?

9. Percentage of Students
We are given:
Part of
Town
Percentage of Students
Number of Students
New Students
South Side
50% ?
North Side
12.5% 6
East Side
37.5%
West Side 0% 2
Total
100%
112

10. Activities and Procedures for Solution:
In order to add the additional students, we need to know how many students there are to begin with.
The percentage of students enrolled from the north side of town
12.5% of 112
Find out how many students
equal 12.5%
12.5% = .125
Multiply 112 by 12.5%
112 * .125 = 14 students
There were initially 14 students from the north part of town enrolled in the program.

11. We continue solving subproblems.
We know there are initially 14 students and that 6 more students came from the north side of town.
The number of students from the north side of town in the first 112 students enrolled 14
Six more students enrolled 6
The total number of students from the north side of town 20
There are now 20 students enrolled from the north side of town.

12. We continue solving subproblems.
We know there are initially no students and that 2 more students came from the west side of town.
The number of students from the west side of town in the first 112 students enrolled
Two more students enrolled 2
The total number of students from the west side of town
There are now 2 students enrolled from the west side of town.

13. Solve another subproblem
In order to find out the percentage of students from the north side of town, we need to know the new total number of students.
The initial number of students in the program
112
Six more students from the north side of town and 2 students from the west side of town enrolled in the program
6 + 2 = 8
The number of students currently enrolled in the program
= 120
There are now 120 students enrolled in the program.

14. Solve another subproblem
We will now divide the number of students currently enrolled in the program from the north side of town by the total number of students enrolled in the program.
The current number of enrolled students from the north side of town 20
The current number of students enrolled in the program
120
The percentage of students enrolled from the north side of town
20 ÷ 120 = 16.67%
The magnet school has 120 students enrolled in the program and 40% are from the north side of town.

15. The final subproblem. . .
We will now divide the number of students currently enrolled in the program from the west side of town by the total number of students enrolled in the program.
The current number of enrolled students from the west side of town 2
The current number of students enrolled in the program
120
The percentage of students enrolled from the west side of town
2 ÷ 120 = 1.67%
The magnet school has 120 students enrolled in the program and less than 2% are from the west side of town.

16. Alternative Strategies:
We could organize the information into a table and perform calculations for all enrollment areas and find out how many students were initially enrolled for each part of town, add the new students and calculate the new percentages for each area.

17. Students Enrolled by Percentage Number of Students Enrolled
Part of
Town
Students Enrolled by Percentage
Number of Students Enrolled
Additional Students Enrolled
New Number of Students Enrolled
New Students Enrolled by Percentage
South Side
50% 56
46.66%
North Side
12.5% 14 6 20
16.67%
East Side
37.5% 42
35%
West Side 0% 2
1.67%
Total
100%
112 8
120

18. Questions?