Problem:
The length of a rectangle is increased by and the width is decreased by . What percent of the old area is the new area?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
A rectangle with length and width has area . The new rectangle has area . The new area is of the old area.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions