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On a $10$ question true/false test, if the questions are answered at random, what is the probability of answering exactly $7$ questions correctly?

I see how $10 \choose 7$ would be choosing $7$ correct answers from $10$ possible answers, but how do I account for the $3$ false answers?

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    Choosing $7$ correct answers corresponds to choosing $3$ incorrect answers.2012-03-23
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    An answer is either true or false. "Choosing 7 correct answers" really means "choosing exactly 7 correct answers", so this accounts for "choosing exactly 3 incorrect answers" as well.2012-03-23

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