Actually, I've read the studio and the theatres split the profits, so a movie needs to make back about 2x what it cost. I have only read that and am no expert so let me know if I'm wrong.
I'm using William Goldman's invaluable how-it's-really-done sourcebooks (Adventures in the Screen Trade, Hype and Glory, Which Lie Did I Tell?, The Big Picture: Who Killed Hollywood?) as my touchstones, chiefly... but: the most recent of these is ten years old, give or take; and I freely admit that circumstances may well have altered since then, given the realities of new retail formats. etc. ;) I, too, am open to any other fellow FReeper expounding further.