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A set of four 3x5 cards is dealt on a
table
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as shown above.
Each card has a letter
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on one side and a
number on the other.
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The dealer proposes that these 4 cards
satisfy the rule:
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“If there is a vowel on one side of the
card,
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then
there is an odd number on the other.”
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What is the smallest number of cards you
have to turn
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over to be sure
the rule is satisfied? Which ones?
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