P18 $6.05,

 P20- $4.00. Is there a possible arbitrage? If so, what is your proposed arbitrage portfolio and what is the present value of your profit? 

 

b) Instead of being able to buy and sell the options at the same price, assume there is a bid/ask spread. P1s- $6.00/$6.05 (bid/ask) and P20 $3.95/$4.05. Now is there a possible arbitrage? What happens to the profitability of the arbitrage portfolio from a)?