How many ways can an IRS auditor select 4 of 8 tax returns for an audit?
combinations of 8 things 4 at a time
8!/[ 4!(8-4)!]
8*7*6*5/(4*3*2*1)
2*7*5
14*5
70
To find the number of ways the IRS auditor can select 4 out of 8 tax returns for an audit, we can use the combination formula.
The combination formula is given by:
C(n, r) = n! / (r! * (n - r)!)
Where:
- n is the total number of items to choose from (in this case, 8 tax returns), and
- r is the number of items to be chosen (in this case, 4 tax returns).
Applying this formula to our scenario, we have:
C(8, 4) = 8! / (4! * (8 - 4)!)
Now let's calculate the factorial values:
8! = 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 40,320
4! = 4 * 3 * 2 * 1 = 24
(8 - 4)! = 4! = 24
Substituting these values into the combination formula:
C(8, 4) = 40,320 / (24 * 24) = 70
Therefore, there are 70 different ways the IRS auditor can select 4 out of 8 tax returns for an audit.