1. **State the problem:** We have a preference table with three columns representing vote counts 8, ?, and 4.
The candidates are A, B, and C ranked in each column as follows:
| Votes | First Choice | Second Choice | Third Choice |
|-------|--------------|---------------|--------------|
| 8 | A | B | C |
| ? | B | A | C |
| 4 | A | C | B |
We want to find the minimum missing vote count $x$ (the "?" column) such that candidate A wins by the Borda count method, but the majority criterion is violated. The majority criterion is violated if candidate B has more than 12 first-place votes (i.e., $x > 12$).
2. **Recall the Borda count method:**
- Each voter ranks candidates.
- For 3 candidates, points are assigned as follows:
- 1st place: 2 points
- 2nd place: 1 point
- 3rd place: 0 points
3. **Calculate Borda points for each candidate:**
Let $x$ be the missing vote count.
- Candidate A:
- From 8 votes: 1st place → $8 \times 2 = 16$
- From $x$ votes: 2nd place → $x \times 1 = x$
- From 4 votes: 1st place → $4 \times 2 = 8$
- Total: $16 + x + 8 = 24 + x$
- Candidate B:
- From 8 votes: 2nd place → $8 \times 1 = 8$
- From $x$ votes: 1st place → $x \times 2 = 2x$
- From 4 votes: 3rd place → $4 \times 0 = 0$
- Total: $8 + 2x + 0 = 8 + 2x$
- Candidate C:
- From 8 votes: 3rd place → $8 \times 0 = 0$
- From $x$ votes: 3rd place → $x \times 0 = 0$
- From 4 votes: 2nd place → $4 \times 1 = 4$
- Total: $0 + 0 + 4 = 4$
4. **Condition for A to win:**
Candidate A must have more points than B and C:
$$24 + x > 8 + 2x$$
Simplify:
$$24 + x > 8 + 2x$$
$$24 - 8 > 2x - x$$
$$16 > x$$
So, $x < 16$.
5. **Condition for majority criterion violation:**
Candidate B has more than 12 first-place votes:
$$x > 12$$
6. **Combine conditions:**
$$12 < x < 16$$
The minimum integer $x$ satisfying both is $x = 13$.
7. **Verify with $x=13$:**
- A's points: $24 + 13 = 37$
- B's points: $8 + 2 \times 13 = 8 + 26 = 34$
- C's points: $4$
A wins with 37 points.
B has $13$ first-place votes, which is more than 12, so the majority criterion is violated.
**Final answer:** The minimum missing vote count is $\boxed{13}$.
Borda Count F306A1
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