2010 AMC 8 Problem 12
Attempt Problem 12 of the 2010 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 2010 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
12.
Of the balls in a large bag, are red and the rest are blue. How many of the red balls must be removed so that of the remaining balls are red?
Answer: D
Small hint:
If red balls are , then blue balls are of the remaining bag.
Big hint:
The number of blue balls stays fixed.
Solution:
If is the number of red balls, then Therefore, if is the number of blue balls, then
If there are red balls after removing balls, then there are blue balls. This means the total number of balls is This means the total number of balls decreased by
Thus, the answer is D .
Problem 12 in other years
- 1985 AMC 8
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