Each week, we post a new Challenge Problem for you to attempt. If you submit the correct answer, you will be entered into that week’s drawing for two free Manhattan Prep GRE Strategy Guides.

At Medville Hospital, Drug X is prescribed only for Condition A and Condition B, which may occur simultaneously in the same patient. Last year, the department recorded the following statistics for prescriptions of Drug X.

Condition	Number of Cases (i.e. Number of patients with the condition)	% of cases in which Drug X was prescribed
A	4,000	25
B	2,000	80

Which of the following could be the number of Medville Hospital patients for whom Drug X was prescribed last year?

See the answer choices and submit your pick over on our Challenge Problem page.