Direct Method : Number of ways to distribute n identical things to r persons such that anyone can get any number of things is (n+r-1)C(r-1)
Let us suppose we want to name somebody with three letters say A,B,C. so what could be the possible names?
ABC, ACB, BCA, BAC, CBA, CAB
Now that was easy to figure out as less number of letters are there. But if we have to find that how many 6 letter names can be made out of English alphabets with…