Let's break down the problem and solve it step by step.
Step 1: Define Variables
- Let \( E \) be the number of students who offer Economics.
- Let \( A \) be the number of students who offer Accounting.
According to the problem:
- \( A = 2E \) (The number of students who offer Accounting is twice those who offer Economics)
- 10 students offer neither subject.
- 5 students offer both Accounting and Economics.
Step 2: Set Up the Equation
In a class of 50 students, those offering at least one of the two subjects can be expressed as: \[ 50 - 10 = 40 \quad \text{(students offering at least one subject)} \]
Step 3: Use the Venn Diagram Variables
From the Venn diagram notation, we have:
- Students offering only Accounting: \( A - 5 \)
- Students offering only Economics: \( E - 5 \)
- Students offering both: 5
- Total students offering at least one subject: \[ (A - 5) + (E - 5) + 5 = 40 \] This simplifies to: \[ A + E - 5 = 40 \] Therefore: \[ A + E = 45 \quad \quad \text{(1)} \]
Step 4: Substitute for A
Using \( A = 2E \) in equation (1): \[ 2E + E = 45 \] This gives: \[ 3E = 45 \] Thus: \[ E = 15 \]
Step 5: Find Number of Students in Accounting
Now, substituting back to find \( A \): \[ A = 2E = 2 \times 15 = 30 \]
Step 6: Summary of Results
Now, we have:
- Students who offer Accounting (\( A \)): 30
- Students who offer Economics (\( E \)): 15
Step 7: Finding Students Offering Only One Subject
- Students who offer only Accounting: \[ A - 5 = 30 - 5 = 25 \]
- Students who offer only Economics: \[ E - 5 = 15 - 5 = 10 \]
Step 8: Total Students Offering Only One Subject
Total students offering only one subject: \[ (30 - 5) + (15 - 5) = 25 + 10 = 35 \]
Thus, the answers to all parts of the question are as follows:
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Venn Diagram Illustration: Place in a Venn diagram with circles for Accounting and Economics, marking:
- "5" in the intersection (students offering both),
- "25" in the Accounting circle (only Accounting),
- "10" in the Economics circle (only Economics).
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Number of Students Who Offer Accounting: 30
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Number of Students Who Offer Economics: 15
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Number of Students Who Offer Only One Subject: 35