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

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= 504/6

9C3= 84ways

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Cricetus Cricetus · Answer 2 · 2022-03-01T12:01:08+01:00

An IRS auditor select 3 of 9 tax returns for an audit in "84 ways".

Permutation and combination:

A permutation seems to be the process of putting things as well as numbers throughout a certain arrangement.

Combinations are becoming a method of picking items or quantities from either a gathering as well as grouping of things in such a manner that perhaps the sequence of the objects is irrelevant.

We know the formula,

→ [tex]nC_r = \frac{n !}{(n-r)! r!}[/tex]

By substituting the values,

= [tex]\frac{9!}{(9-3)!3!}[/tex]

= [tex]\frac{9\times 8\times 7\times 6!}{(6)! 6}[/tex]

= [tex]\frac{9\times 8\times 7}{6}[/tex]

= [tex]\frac{504}{6}[/tex]

= 84 ways

Thus the above answer is correct.

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https://brainly.com/question/11732255