Nitin Is Paid on a Graduated Commission Scale

Multiple Choice

Nitin is paid on a graduated commission scale. He receives commission at the rate of 2.5% for the first $5,000 of sales in a week, 4% on the next $10,000, and 4.5% on all further sales. What is Nitin's average rate of commission in a week in which his sales are $30,000?

A) 3.67%
B) 4%
C) 3.33%
D) 3.75%
E) 4.25%