Mike can be paid in one of two ways based on the amount of merchandise he sells:

Plan A: A salary of $900.00 per month, plus a commission of 9% of sales, OR Plan B: A salary of $1,100.00 per month, plus a commission of 11% of sales in excess of $9,000.00.

For what amount of monthly sales is plan B better than plan A if we can assume that Mike's sales are always more than $9,000.00? Write your answer an an inequality involving x, where x represents the total monthly sales.