Err, a little confused. Options

[Mikeplyts]

So today I was in art class and we were making our own paintings of whatever we wanted and such. Then, an interesting question popped in my mind and it was a question which I thought was never really important but I asked it anyways to a few of my friends.
Here's my question.

Are black/white colors?

Yes, I know it's a little stupid but I've never really thought about it. One of my friends said they are because you are able to make or "color" things with black/white. Another disagreed and made an interesting point that black is what attracts all colors and white reflects all colors therefore, they aren't colors. The first one also said that all the colors together make black and all the colors taken away make white. He also added that they were colors said that they are colors because if you mix them, you can make another color (in this case, gray). Now, I'm a bit confused on whether black/white are colors or not. My friend who disagreed did make a good point so I think black/white are not colors but then again, I could always be wrong.

Any opinions?