求救！马上就考了，一道prep数学，跪谢！

4) A certain office supply store stocks 2 sizes of
self-stick notepads, each in 4 colors: blue, green,
yellow, or pink. The store packs the notepads in
packages that contain either 3 notepads of the same
size and the same color or 3 notepads of the same size
and of 3 different colors. If the order in which the
colors are packed in not considered, how many
different packages of the types described above are
possible?

不理解这题，我想了N久都想不通~~~~~~

2 sizes and 4 colors:
Size 1: B,G,Y,P --->(A)
Size 2: b,g,y,p ---> (B)

3 notepads of same size and 3 different colors:
choose 3 notepads from B,G,Y,P and choose 3 notepads from b,g,y,p
=> 4C3 + 4C3 = 8

3 notepads of same size and same color:
这就是我不明白的地方了！！Referring back to (A) and (B), how can we select 3 notepads of same size and SAME COLOR?

有两个size 的notepads, 每一个size4中颜色

两种packages

1 same size same color: 每一个SIZE有四种颜色，所以四种取法，合计4*2

2 same size different color: 每一个PACKAGE含有三种不同颜色， 那就是C4，3， 合计2*C4，3

最后共有4*2+2*C4，3