Question: How many ways can five bills from a money drawer with seven denominations be selected?
For example, if we chose two $50 bills, a $10 bill, a $5 bill and a $2 bill the arrangement would look like
| x x | | x | x | x |
$100 $50 $20 $10 $5 $2 $1
These 11 items can be arranged C(11,5) (or C(11,6)) different ways.
Notice that there are 6 separators because there are 7 denominations.