18. School A and School B each send out $\mathbf{5}$ students to participate in a long-distance running competition, with the rule being: The $\mathbf{K}$-th student to reach the finish line scores $\mathbf{K}$ points (no students arrive at the finish line simultaneously), and the school with the lower total score wins. Therefore, the winning team's total score has () possible outcomes.
【Answer】13
【Analysis】There are 10 students, scores are $1 \sim 10$, the total score is 55 points, all scores are integers. To win, the maximum score is 27 points, the minimum score is $1+2+3+4+5=15$, within the range of 15 to 27. There are $27-15+1=13$ kinds, and all 13 kinds can be achieved.