Problem:

Columns A & B list the sales totals and IDs of five salespersons. We want to calculate each person\'s commission based on ranking in total sales, as per the following scheme:
Highest sales total - 15%
2nd highest total - 12%
3rd highest total - 10%
4th highest total - 8%
5th highest total - 5%

Solution:

Use the CHOOSE and RANK functions in the following formula:
=CHOOSE(RANK(B2,$B$2:$B$6),15%,12%,10%,8%,5%)*B2