Ten different letters of English alphabet are given. Out of these letters, words of letters are formed. How many words are formed when at least one letter is repeated?
Explanation for the correct answer:
Given ten different letters of alphabets.
Number of words of letters formed by repeating all these letters
Number of words of letters formed by not repeating any of these letters
Hence, the number of words of letters formed by repeating at least one of the letters
Therefore, the correct answer is option (A)