@The-Blade-Dancer I've improved the explanation in the course a bit, so hopefully it is more understandable now. https://daily.poshenloh.com/courses/take/3-combinatorics/quizzes/11132409-day-12-your-turn-explanation-2-of-3 Your answer of 24 is just too small by a factor of 4, so I wonder if you had the right idea but just forgot to multiply by some number of choices. I will be able to troubleshoot more if you can tell me some of the steps that you used. For example, what did you get for the total number of ways? And what did you get for the number of "bad" ways?