Find values A, B and C and multiply them

Two old ladies were outside their nursing home having a smoke, when it started to rain. One of the ladies pulled out a condom, cut off the end, put it over her cigarette, and continued smoking.
Lady 1: What's that?
Lady 2: A condom.
Lady 1: Where'd you get it?
Lady 2: You can get them at any drugstore.
The next day, the first lady hobbled into the local drugstore and announced to the pharmacist that she wanted to buy a package of condoms.
The guy looked at her kind of strangely (she was, after all, in her 80s), but politely asked what brand she preferred.

"Doesn't matter," she replied, "as long as it fits a Camel."