Ten different letters of the alphabet are given. Words with five letters are formed from these given letters. Then the number of words that have at least one letter repeated is?
Explanation for the correct answer:
Counting of numbers:
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, number of words of letters formed by repeating atleast one of the letters
Therefore, the correct answer is option (A).