Ann Wills is offered a sales job with two firms. Boden Tools offers her a salary of $800 a month, a commission of 3% on total monthly sales, and 3% more on monthly sales over $75,000. Sentor, Inc.
offers her a commission of 2.5% on the first $45,000 of monthly sales, 4.5% on the next $20,000 of
monthly sales, and 7% on all monthly sales over $65,000. If Ann could average $87,000 in sales a month
at either job, at which job could she earn more per month, and how much more?