Algebra-1

Question Analysis
This question tests the student's ability to calculate the new marginal relative frequency after the total number of students changes. The marginal relative frequency is the ratio of the number of 10th-grade students to the new total number of students.

Key Concept Explanation
Marginal Relative Frequency: It is obtained by dividing a marginal frequency (the number of 10th-grade students) by the new total number of the population (total number of students after the increase).

Step-by-step Solution
1. Identify the initial number of 10th-grade students: 80.
2. Identify the number of new 10th-grade students: 50.
3. Calculate the new number of 10th-grade students: 80 + 50 = 130.
4. Identify the new total number of students: 200 + 50 = 250.
5. Calculate the new marginal relative frequency: .
6. Simplify the fraction: