Problem:
The average age of 33 fifth-graders is 11 . The average age of 55 of their parents is 33 . What is the average age of all of these parents and fifth-graders?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The sum of all the ages is , so the average of all the ages is
The problems on this page are the property of the MAA's American Mathematics Competitions