An Investor Believes That Xyz Stock Will Decline In The Upcoming 6 Months And As

An investor believes that XYZ stock will decline in the upcoming 6 months and as such buys one put option at a strike price of $40. The stock is currently trading at $42 a share. The investor pays $3 a share for the premium. What is the investor’s maximum possible gain and maximum loss? What is the maximum gain and loss for the writer of the put?