NSH109 Wrote:"....Model A and Model B, each of which is available in four colors: blue, black, red, and green..."
Sorry but I do not understand the wording of this problem. So if a product comes in 4 colors (or available in 4 colors), there are only exactly 4 items of that product? since I did not know how to make of this, I struggled with this problem for quite a long time.
^^ this is irrelevant, because the problem is about combinations of three different cars.
i.e., you're wondering whether it's possible to have more than one of the same car in the same color -- but that doesn't matter here, since any such duplication would be excluded from consideration anyway.