Question

An election ballot asks voters to select two city commissioners from a group of four candidates. In how many ways can this be done?

Answer 1

Let n = 12
Let r = 6
Replace every n! with 12 and every r! with 6 and then do the math.
nCr = 12!/[(12 - 6)!*6!]
nCr = 479001600/(720)(720)
nCr = 479001600/518400
nCr = 924
There are 924 ways or combinations to select 6 city commissioners from a group of 12 candidates