# Easy Permutation-Combination Solved QuestionAptitude Discussion

 Q. Ten different letters of alphabet are given, words with 5 letters are formed from these given letters. Then, the number of words which have at least one letter repeated is:
 ✔ A. 69760 ✖ B. 30240 ✖ C. 99748 ✖ D. 42386

Solution:
Option(A) is correct

Number of words which have at least one letter replaced:

$= \text{Total number of words - total number of words in which no letter is repeated}$

$⇒{10}^5 – {^{16}P_5}$

$⇒100000 - 30240$

$= 69760$

## (1) Comment(s)

Kamal
()

Please correct the solution it would be

${10}^5 - ^{10}P_5$