Can somebody explain me why here the order matters (from GregMat quizzes)? The answer is 555, which is the sum of two permutations (where order matters), while to me this should be less than 555 as these are combinations.
not sure why order matters as whether you use permutation or combination formula should get you the same result (in the context of this question due to the numbers - normally it does), but this looks like an arrangement problem.
I got 555 by adding the 3 cases together. RG + BG + RGB =>7x5+13x5+7x13x5