The interest rate is 3% per year compounded monthly. Deere stock is trading at $169. A European put option expiring in eight months has a strike price of $160 and is trading at a premium of p=$18.50. No dividend payment is expected. A dealer quotes the otherwise identical call option at $27.23 bid, $27.73 ask. How much arbitrage profit can one make based on this information?

My professor's solution is this:

Using put-call parity adjusted for a known dividend, by writing a put, shorting a share and lending the PV of the strike. From the t=0 column of our arbitrage table, we find the profit as the sum of the cash flows of these four transactions, -27.73+18.50+169-160.00/1.020175878=$2.93.

My question is how was the 1.020175878 calculated?