Explain this step by step: Gerald purchased 3 put option contracts at an option premium of $0.95 and a strike price of $40. At expiration, the stock price was $42.25 per share. What is his percentage...

Explain this step by step:

Gerald purchased 3 put option contracts at an option premium of $0.95 and a strike price of $40. At expiration, the stock price was $42.25 per share. What is his percentage return? What is the percentage return if the stock price at expiration is $39.05?  What is the percentage return if the stock price at expiration is $36.18?