Problem:
Kayla rolls four fair -sided dice. What is the probability that at least one of the numbers Kayla rolls is greater than and at least two of the numbers she rolls are greater than ?
Answer Choices:
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B.
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E.
Solution:
Kayla's rolls have the required properties if and only if it is not the case that she rolls four numbers less than 5 , or she rolls one number greater than 4 and the other three numbers less than 3. This occurs with probability
The problems on this page are the property of the MAA's American Mathematics Competitions