Problem:
In a bag of marbles, of the marbles are blue and the rest are red. If the number of red marbles is doubled and the number of blue marbles stays the same, what fraction of the marbles will be red?
Answer Choices:
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Solution:
The ratio of blue marbles to red marbles is . If the number of red marbles is doubled, the ratio will be , and the fraction of marbles that are red will be .
The problems on this page are the property of the MAA's American Mathematics Competitions