You can
put this solution on YOUR website! .
M I S S I S S I P P I
11 letters.
4 "I"s
4 "S"s
2 "P"s
The answer is 
,
where 4! in the denominator stands for 4 repeating "I"'s;
another 4! in the denominator stands for 4 repeating "S"'s;
and 2! in the denominator stands for 2 repeating "P"'s.
Solved.
================
See the lesson
- Arranging elements of sets containing indistinguishable elements
in this site.
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic "Combinatorics: Combinations and permutations".
Save the link to this textbook together with its description
Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson
into your archive and use when it is needed.
