Problem:
The grid shown contains a collection of squares with sizes from to . How many of these squares contain the black center square?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
All of the squares of size , and contain the black square and there are
of these. In addition, of the squares and of the squares contain the black square, for a total of .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions