3. A stock is currently selling for $78 per share. A call option with an exercise price of $81 sells for $3.90 and expires in three months. If the risk-free rate of interest is 2.7 percent per year, compounded continuously, what is the price of a put option with the same exercise price? (Do not round intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.)