A European call option where S = 16, K = 15, T = 0.25, r = 1% and Vol = 25% has a current B-S value of $ 1.39 per share. This call also sells in the market at the value of $139. The vega is 2.66 and the theta is 1.435. Given that

1. What may be the total premium if Vol goes up to 28% under ceteris paribus assumptions?
2. What may be the total premium after 4 days under ceteris paribus assumptions?

In the problem above in which the B-S value for premium is $ 139; assume that the market value of premium is $ 146. Apparently there is an arbitrage possibility. What you must do to have an arbitrage gain? Assuming that you implement arbitrage by 1000 calls; what may be your arbitrage gain?