Problem:
The average age of the members of a computer science camp is years. There are girls, boys, and adults. If the average age of the girls is and the average age of the boys is , what is the average age of the adults?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The sum of all ages is . The sum of the girls' ages is and the sum of the boys' ages is . The sum of the five adults' ages is . Therefore, their average is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions