Given the following two strings of words: "Bobo, Mississippi" and "Soso, Mississippi", what is the difference in the amount of four letter sequences that can be formed by using theirs letters (excluding spaces and commmas)?
I believe each can be calculated by choosing 4 letters each time from the string.
For Bobo: Let $x = b + o + m + i + s + p$, where each letter (except x) is the number of that letter in the given string.
Then I can do:
$\Sigma_{x=4} \frac{4!}{b!o!m!i!s!p!}$
What this should mean is, find the permutations of length 4 such that the letters are distributed to have the amount of letters summing to 4. Then add up the amount of permutations for each. However, I'm not really sure how I'm supposed to solve this.
I'm not even sure if this approach is correct. If there is another method to solving this that is easier, I would really appreciate if it were explained to me.