1999 AMC 8 Problem 13
Attempt Problem 13 of the 1999 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1999 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
13.
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: C
Small hint:
Convert each average into a total age
Big hint:
Subtract the girls’ and boys’ totals from the camp total
Solution:
The sum of the ages of everybody at the camp is
The sum of the ages of the girls is and of the boys is
As such, we know that the ages of the adults must be
And therefore, the average age of the adults is then
Thus, C is the correct answer.
Problem 13 in other years
- 1985 AMC 8
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