In a classroom, there are 12 students who scored above avera...

Question Analysis
This question tests the application of the closure property of real numbers in a real-world context.

Key Concept Explanation
The closure property ensures that the sum of any two real numbers (in this case, the number of students) remains a real number.

Step-by-step Solution
1. Identify the number of students above average: 12.
2. Identify the number of students below average: 8.
3. Add the numbers: