我们来讨论如下一道概率问题:将1,2,3,4,5,6填入如图1所示的三角形的6个圈中,每个数恰在三角形中出现一次,求填数后三角形3边上的数字之和相等的概率.显然,将1,2,3,4,5,6填入图1的三角形中的填法共有6!种,下面我们讨论三边上的数字之和相等的填法种数.设每条边上的3数之和均为s Let’s discuss the following probabilistic problem: Fill 1,2,3,4,5,6 into the six circles of the triangle shown in Figure 1. Each number appears exactly once in the triangle, after the number of triangles The probability that the sums of the numbers on the 3 sides are equal. Obviously, there are 6! kinds of filling methods for filling 1,2,3,4,5,6 into the triangles of Fig. 1. Next we discuss the sum of the numbers on the three sides. Equal fill method. Set the sum of 3 on each edge to be s