A trader creates a long butterfly spread from put options with strike prices of $160, $170, and $180 per share by trading a total of 20 option contracts (5 contracts at $160, 10 contracts at $170 and 5 contracts at $180). Each contract is written on 100 shares of stock.

The options are worth $22, $28, and $36 per share of stock. What is the value (payoff) of the butterfly spread at maturity as a function of the then stock price?

What is the profit of the butterfly spread at maturity as a function of the then stock price?