Denim Company offers sales people the following commission structure, with commission being paid monthly: 1.00% on the first $2,000 they sell, 3.00% on the next $3,000 they sell, and 4.50% thereafter on all sales they make. Megan, a new sales representative, made sales of $2,500 in his first month, $6,000 in his second month, and $5,200 in his third month. a. What were his total commissions for the first three months? b. What single commission rate would represent his total earnings throughout the first 3 months