I was able to get the Ask Price as $311.

The purchase price = 31130-(100*0.5)= 31100 --> 31100/100 shares = $311 ASK

I'm not sure what to do after given the total transaction cost = $243

4. Alex buys 100 shares of the stock of Apple at the same time that Neil sells 100 shares of the stock of Apple. The commission on Alex's purchase is 0.50 per share while the commission on Neil's sale is 0.3% of the price. Alex pays 31,150 to purchase his 100 shares. The total transaction costs incurred by both Alex and Neil are 243.00 Calculate the Bid Price for one share of Apple