Question

So you have 21 people that you want to have meet in groups of 3. How many rounds of meeting would it take to have them all meet?

Answer 1

1330 rounds of meetings

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 =
`(n!)/(r!(n-r)!)`

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:

->
`(21!)/(3!(21-3)!)`

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