Using calls, a long butterfly spread can be constructed by buying one lower striking in-the-money call, writing two at-the-money calls and buying another higher striking out-of-the-money call. A speculator decides to create a butterfly spread involving the following 3 one-year European call options on a stock with exercise prices (and corresponding call premia in parentheses): $40 (premium $3), $45 (premium $2.30) and $50 (premium $2). For what values of the yearend stock price will profits be generated?