In how many ways can the letters {U, U, R, R} be arranged?
Choices.
A) 4  B) 20  C) 120  D) 720  E) 840
My answer : 4   There is 4! ways to arrange those letters in total, however letter U repeats 2! times and letter R repeats 2! times   =&gt; the way to arrange without repeating = 4!/ [2!x2!] = 4
<result>A</result>
In how many ways can the letters {U, U, R, R} be arranged?