How many dozen pens is the man ordering?

Man I need twelve dozen ballpoint pens, and they need to be different colors. Let’s see. . . . Make it six dozen red pens, four dozen black, and two dozen purple.
Woman I’ll have to check for the purple. Hmm . . . yes, we have purple. OK, your total for twelve dozen pens comes to seventy-five dollars exactly, including tax.
Man Let me see what I have in my wallet. Oh, yes, here’s a one-hundred dollar bill.