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# help

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A list consists of all possible three-letter arrangements formed by using the letters A, B, C, D, E, F, G, H such that the first letter is D and either the second or third letter is A. If no letter is used more than once in an arrangement and one three-letter arrangement is randomly selected from the list, what is the probability that the arrangement selected will be DCA?

Feb 17, 2020

$$\text{Pick whether A is second or third. That's two choices. Pick the remaining letter. That's 6 choices}\\ \text{Thus a total of 2\cdot 6 = 12 choices meeting the requirements}\\ p = \dfrac{1}{12}$$