Sue's monthly earnings consist of a monthly salary and a 4 percent commission on the portion of her monthly sales that is in excess of $2,000. If Sue's monthly salary was the same in July as in August, how much greater were her sales in July than in August?
(1) Sue's monthly earnings were $3,620 in July and $3,580 in August.
(2) Sue's monthly salary was $3,500 in July and in August.
(1) is sufficient. The difference between $3620 and 3580 is the difference between the 4% of the commision of her sales in July and in August.
Earnings July = salary + 4%Sales in July
Earnings August=salary+4%sales in August
--->4%(Sales in July-Sales in August)=Earnings in July - Earnings in August.
--->(Sales in July-Sales in August)=(Earnings in July - Earnings in August)/0.04
(2) is not sufficient since is not possible to calculate the sales revenue for each month.
So the correct answer is A