A put is the option to sell stock at $50. It expires after three months and currently

Question:

A put is the option to sell stock at $50. It expires after three months and currently sells for $3 when the price of the stock is $52.
a. If an investor buys this put, what will the profit be after three months if the price of the stock is $55? $50? $45?
b. What will be the profit from selling this put after three months if the price of the stock is $55? $50? $35?