You can put this solution on YOUR website!
Based on where you gave the problem seems like you think we are going to use permutations......in fact you are right, we will :-). And that should also be the first question in this type of problem. Are we going to use permutations or combinations? in other words, does order matter? Does matter whether we first choose black or green color to paint first room ?
-these are two permutations, but just one combination
So, yes it does and whenever it does we use permutations.Another important question is, can we repeat the colors? Can we paint all rooms black? Yes we can and thus we are going to use permutations with repetition(
). Equation is
, where n is number of things we choose from and k is number of things we choose.(From 15 colors(n) we choose 4(k)-we choose 4 colors because there are only 4 rooms-for every room - 1 color) Given that we have