Problem:
A store owner bought  pencils at  each. If he sells them for  each, how many of them must he sell to make a profit of exactly 
Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
Since he bought pencils at each, he paid . To make profit he must take in . Therefore, selling the pencils for each, he must sell pencils.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions