Respuesta :

Answer:

1330 rounds of meetings

Step-by-step explanation:

You have a total of 21 people, and  they all want to meet with each other in groups of 3. This means we are dealing with a combination problem, where combination is the selection of items in which order does not matter.

Formula for combination:

ₙCᵣ = [tex]\frac{n!}{r!(n-r)!}[/tex]

where n is the total number of objects (in this case, total number of people: 21), and r is the sample set (in this case, groups: 3).

We plug in and get:

-> [tex]\frac{21!}{3!(21-3)!}[/tex]

-> 1330 different meetings for everyone to meet with each other in groups of 3.