13. (3 points) The judging panel of the Young Singers Grand Prix consists of several people. Each judge gives a score to the singer, with a maximum of 10 points. After the first singer performs, the scoring situation is as follows: the average score given by all judges is 9.64 points; if the highest score is removed, the average score of the remaining judges is 9.60 points; if the lowest score is removed, the average score of the remaining judges is 9.68 points. Therefore, the lowest score given by all judges can be at least $\qquad$ points, and the number of judges in this Grand Prix is $\qquad$.
13. (3 points) The judging panel of a young singer grand prix consists of several people. Each judge can give a singer a maximum score of no more than 10 points. After the first singer performs, the scoring situation is as follows: the average score given by all judges is 9.64 points; if the highest score is removed, the average score of the remaining judges is 9.60 points; if the lowest score is removed, the average score of the remaining judges is 9.68 points. Therefore, the lowest score among all the judges can be at least $\qquad$ points, and there are $\qquad$ judges in this grand prix.

【Solution】Let the number of judges be $x$, then the total score is $9.64 x$; the total score after removing the highest score is $9.60(x-1)$, from which we can deduce that the highest score is $9.64 x - 9.60(x-1) = 0.04 x + 9.6$; the total score after removing the lowest score is $9.68(x-1)$, from which we can deduce that the lowest score is $9.64 x - 9.68(x-1) = 9.68 - 0.04 x$. Since the highest score does not exceed 10, we have $0.04 x + 9.6 \leqslant 10$, which means $0.04 x \leqslant 0.4$, so $x \leqslant 10$. When $x$ is 10, the lowest score has the minimum value of 9.28 points, and there are 10 judges, hence the answer is: $9.28, 10$