A company offers two options for sales partners: $150 plus a 6 percent commission weekly or a flat 11 percent commission. Mrs. Lee, the top salesperson in the company, averages $3500 a week in sales. Which option should she take, and why?

(Source: Mathematics Teaching in the Middle School, May 1998)

Flat commissions are rewarding if sales partners make enough sales. What is the minimum weekly average for sales that Mrs. Lee needs in order for Option 2 to give her more money than Option 1.