Question

Problem 2.8. Consider a language containing four letters: A, B, C, D. How many three-letter words can you form in this language? How many four-letter words can you form if each letter appears only once in each word?

Answer 1

Possible 3 letter words=4!/(4-3)!=24 (if no repetition of letters is done)
If there is repetition of letters= 64 possibilities
Therefore total possibility of 3 letter words= 88

Possible 4 letter words(no repetition)=24