Can you assist with the following question and illustrate how to solve it? It doesn't provide a risk-free rate, so I'm not sure if its necessary to have one in order to determine if there is an arbitrage opportunity.

Consider a forward contract on IBM requiringpurchase of a share of IBM stock for $150 in sixmonths. The stock currently sells for $140 a share.Assume that it pays no dividends over the comingsix months. Six-month zero-coupon bonds are

selling for $98 per $100 of face value.

a. If the forward is selling for $10.75, is there an arbitrage opportunity? If so, describe exactly

how you could take advantage of it.

b. Assume that three months from now: (i) the stock price has risen to $160 and (ii) three-month zero coupon bonds are selling for $99. How much has the fair market value of your forward contract changed over the three months that have elapsed?