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I'm trying to solve the following question which is in the permutations unit:

In how many ways can all the letters of the word CANADA be arranged if the consonants must always be in the order in which they occur in the word itself?

I have no idea where to start, any hints would be appreciated!


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up vote 6 down vote accepted

Select three out of six positions for the consonants, fill tme in order, then fill the rest with "A"s. So that's $6\choose 3$.

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