Three put options on a stock currently selling for $50 have the same expiration date and strike prices of $45, $50, and $55. The market prices are $4, $6, and $10 respectively.

1. Explain how a butterfly spread can be created from these three options.
2. Construct a table showing the payoff and profit from this strategy for different values of S_T.
3. Sketch the profit as a function of S_T.
4. For what values of S_T does the butterfly spread result in a loss?