Television and radio stations use four call letters starting with W or​ K, such as WXYZ or KRLD. Assuming no repetitions in the second to fourth​ letters, how many​ four-letter sets are possible using either W or K and only the letters Upper I to Upper Y​? ​(Count all possibilities even​ though, practically, some may be​ inappropriate.)
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Part 1
There are

enter your response here ​four-letter sets that can be formed.