Combinatorics QUESTION 2-3

Let $\displaystyle A = {a_1, a_2, . . . , a_k}$ be an alphabet, and let $\displaystyle n_i$ denote the number of appearances of

letter $\displaystyle a_i$ in a word. How many words of length n in the alphabet A are there for which

$\displaystyle k = 3, n = 10, n_1 = n_2 + n_3 $and $\displaystyle n_2$ is even?

Re: Combinatorics QUESTION 2-3

Hey maximus101.

Can you show us what you have tried? Is a word just a string of the same letter? If you have to have a separator between the words thn gives a hint of the upper limit of words.