8. (10 points) A certain exam consists of 7 questions, each of which only concerns the answers to these 7 questions, and the answers can only be one of $1, 2, 3, 4$. It is known that the questions are as follows:
(1) How many questions have the answer 4?
(2) How many questions do not have the answer 2 or 3?
(3) What is the average of the answers to questions (5) and (6)?
(4) What is the difference between the answers to questions (1) and (2)?
(5) What is the sum of the answers to questions (1) and (7)?
(6) Which question is the first one with the answer 2?
(7) How many answers are unique to only one question?
Then, the total sum of the answers to the 7 questions is $\qquad$
【Solution】Solution: Since the answer to each question is one of $1, 2, 3, 4$,
the answer to (1) should not be too large, let's take 1,
at this point, the answer to (2) is actually the number of 1s and 4s among the 7 answers, which can only be one of $2, 3, 4$. If we take 2, it means that only one of the remaining questions can have the answer 1, which would be (4) filling 1, (7) filling 2, (5) filling 3, (6) filling 2, and (3) cannot fill an integer, which contradicts the problem;

Therefore, the answer to (2) should be 3, which means that among the remaining questions, there is one answer of 1 and one answer of 4. At this point, (4) fills 2, and (7) can only fill 1, so (5) fills 2, then 4 should be the answer to (6), thus (3) fills 3,

At this point, the answers to the 7 questions are as follows:
\begin{tabular}{|c|c|c|c|c|}
\hline Question Number & 1 & 2 & 3 & 4 \\
\hline 1 & $\mathcal{V}$ & & & \\
\hline 2 & & & & \\
\hline 3 & & $\checkmark$ & & \\
\hline 4 & & & & \\
\hline 5 & & & & \\
\hline 6 & & & & \\
\hline 7 & & & & \\
\hline
\end{tabular}

Their sum is $1+3+3+2+2+4+1=16$.