Problem:
Maria buys computer disks at a price of for and sells them at a price of for . How many computer disks must she sell in order to make a profit of
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Since the computer disks are bought in groups of and sold in groups of , it is easier to consider them in groups of or dozens. Each dozen costs and sells for giving a profit of . Thus to get a profit of , she must sell dozen or computer disks.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions