+771 In how many ways can the letters A, B, C and D be arranged so that no letter is adjacent to any letter that comes immediately before it or immediately after it alphabetically?
I understand there are 4! ways to arrange the letters A, B, C, D without any constraints.
What method should I use here? Complementary or constructive?
I will start with complementary.
There are 4! ways w/out constraints.
Let's see how many ways there are to arrange the letters so that every letter IS adjacent to the letter that comes immediately before or immediately after it.
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o _ O How will I find this? Help is appreciated! :D
+60 I might not be correct, but I think it's 2. I don't have time to show a solution, but I will about 30 min. later.
+771 xD I think I might have figured it out!
There's just BDAC and CADB
So it's just 2 ways, I think?
+60 Yes, but I wanted to give a big explanation. Since you got it, I don't need to do it xD
