Roslyn has twenty boxes. Thirteen of the boxes contain pencils, nine of the boxes contain pens, and three of the boxes contain neither pens nor pencils. How many boxes contain both pens and pencils?
Question:
Roslyn has twenty boxes. Thirteen of the boxes contain pencils, nine of the boxes contain pens, and three of the boxes contain neither pens nor pencils. How many boxes contain both pens and pencils?
Answer:
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Roslyn has twenty boxes. Thirteen of the boxes contain pencils, nine of the boxes contain pens, and three of the boxes contain neither pens nor pencils. How many boxes contain both pens and pencils?
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