ten different letters of an alphabet is given. words with five letters are formed from these given letters.then the number of words which have atleast one letter repeatted is69760.prove it?

Dear manisha

total number of words of 5 letter from 10 different letter such that any letter can be repeated any number of time = 10⁵

total number of words of 5 letter from 10 different letter such that no letter can be repeated  = 10 *9*8*7*6

now for atleast one letter is repeated = 10⁵ - 10 *9*8*7*6

                                                     =69760

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