6. (12 points) $A, B, C$ three people are guessing a natural number between $1 \sim 99$.
A: “It is an even number, less than 6.”
B: “It is less than 7, a two-digit number.”
C: “The first half of A's statement is true, the second half is false.”
If among these 3 people, 1 person tells two truths, 1 person tells two lies, and 1 person tells one truth and one lie. Then, this number is . $\qquad$
6. (12 points) $A, B, C$ are guessing a natural number between $1 \sim 99$.

A: “It is an even number, less than 6.”
B: “It is less than 7, and it is a two-digit number.”
C: “The first half of A's statement is true, the second half is false.”
If among these 3 people, 1 person tells two truths, 1 person tells two lies, and 1 person tells one truth and one lie. Then, this number is $\qquad$ 8 .

【Solution】According to the analysis, it is clear that B's two statements contradict each other, so B's statements cannot both be true. We can infer that one of A and C must be the one who tells two truths. Assume A tells two truths, then one of B and C must tell two lies. Since B says “it is less than 7” which is true, B cannot be the one who tells two lies.

Therefore, C must be the one who tells two lies. If C tells two lies, then A must have one lie, which is a contradiction. Hence, A cannot be the one who tells two truths. Thus, we can conclude that C is the one who tells two truths; A is the one who tells one truth and one lie; and B is the one who tells two lies. Therefore, we can determine that the number is even, greater than 7, and not a two-digit number. It must be a single-digit number, and the only even number greater than 7 is 8.

Therefore, the answer is: 8.