Question
Question: 10 different letters of an alphabet are given words with 5 letters are formed from these letters. Th...
10 different letters of an alphabet are given words with 5 letters are formed from these letters. Then the number of words which have at least one letter repeated, is –
A
69760
B
30240
C
99784
D
None of these
Answer
69760
Explanation
Solution
At least on letter repeated = Total words – words in which repetition is not allowed.
= 105 – 10P5