Take these seven people as a group and the other 25 people as a group. Then the following scheme:
Two people were randomly selected from 25 people to participate in the competition. * * * There are C25(2) = 25*24/2 = 300 species;
Randomly draw 1 person from 25 people, and draw 1 person from these 7 people to compete. * * There are: C25 (1) * C7 (1) =175 species.
That is to say, in the above-mentioned lottery combination of 300+ 175 = 475, it is absolutely guaranteed that these seven people will not meet.
Of course, the total lottery combination * * = C32 (2) = 32 * 3 1/2 = 496.
Therefore, the probability is:
= 475/496 * 100%
≈ 95.77%