Probability and Statistics question on sequences and vowels

Question

How many 4-letter “words” (sequences of letters with repetitions allowed) in which vowels appear only (if at all) as the first and last letter?

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Answer 1

This is equivalent to calculating the number of 4 letter words with no vowels in positions 2,3. This gives $26^2\cdot 21^2$ because all letters are valid is the 1st and 4th positions.