Question 1165255: in how many ways can the letter of the word "HELL" be permuted, if the two 2LLs must always be apart. Found 2 solutions by ikleyn, math_helper:Answer by ikleyn(52778) (Show Source):
There are 4! = 4*3*2*1 = 24 permutations of 4 letters, in all.
From this amount, subtract those permutations, where two letters "L" go together.
The number of such permutations is 2*3! = 2*6 = 12.
The difference 24 - 12 = 12 is the number of wanted permutations in your problem. ANSWER
