Question

How many ways can an IRS auditor select 3 of 9 tax returns for an audit?

Answer 1

Answer:

84ways

Step-by-step explanation:

This is a problem on combination. Combination has to do with selection. For example if r objects are to be selected from a pool of n objects, this can be done in nCr ways.

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

9C3= 9!/(9-3)!3!

9C3= 9!/(6)!3*2*1

9C3= 9*8*7*6!/(6)!6

9C3= 9*8*7*/6

9C3= 9*8*7*/6

9C3= 504/6

9C3= 84ways