We want to choose a committee of 3 people from a total number of 10 people. This is a case of combination. The formular for combination is expressed as
n!/k!(n - k)!
Where
n represents the total number of people that we want to choose from.
k represents the number of people that we want to choose.
n = 10
k = 3
Therefore, the number of ways would be
10!/3!(10 - 3)!
10!/3! * 7!
=
k