There are four letters in LLRR, so there would be 4! possible different arrangements. However, there are two repeating letters, so we have to divide by 2!2! to account for overcounting: 4!/2!2! = 4*3*2/4 = 6, so there are six possible different arrangements of the word LLRR.
(If you're asking for a ratio of the permutations of LLRR vs the permutations of ROLLER, then do 6/(6!/6), where 6!/6 accounts for the arrangements of the word ROLLER and 6 accounts for the arrangements of the word LLRR.)
There are three letters in ROR, so there would be 3! possible different arrangements. However, there is one repeating letter, so we have to divide by 2! to account for overcounting: 3!/2! = 6/2 = 3, so there are three possible different arrangements of the word ROR.
(If you're asking for a ratio of the permutations of ROR vs the permutations of ROLLER, then do 3/(6!/6), where 6!6 accounts for the arrangements of the word ROLLER and 3 accounts for the arrangements of the word ROR.)
I hope I helped!