Answer:
169911 groups of 5 participants are possible
Step-by-step explanation:
Total no. of participants = 31
We are supposed to find no. of groups of 5 participants are possible
We will use combination over here :
Formula : 
Substitute r = 5
n = 31
So,no. of groups of 5 participants are possible =
So,no. of groups of 5 participants are possible:

Hence 169911 groups of 5 participants are possible