please help me with all of these questions

(Bonus question: What is the Adi Close price? ("Adjusted Close" price: adjusted how?) f) If you had bought 100 shares of this stock 1 year ago, and sold it today, how much money would you have made or lost? (If the market wasn't open exactly 1 year ago, or today, use the closest day the market was open.) 4. The order book for a stock looks like the following table. Samantha and Nguyen both want to buy (up to) 1000 shares in this stock. Samantha places a limit order for 1000 shares @ $20. Nguyen places a market order for 1000 shares. Ask Volume Price 18.00 19.50 Bid Volume 500 500 1000 19.75 100 19.80 20.00 20.25 20.50 21.00 200 200 500 1000 a) How many shares does Samantha get? How much does she pay per share? What does the order book look like after her order is processed? b) How many shares does Nguyen get? What price(s) does he buy them at? How much does he pay per share? What does the order book look like after his order is processed? c) Who is happier, Samantha or Nguyen? One year later the order book looks like the following table, and they both decide to sell the shares they bought. Samantha places a limit order to sell her shares at $21. Nguyen places a market order to sell his shares. Ask Volume Price 20.00 20.50 Bid Volume 500 100 1000 500 20.60 20.80 21.00 21.50 22.00 22.25 500 200 500 4000 a) How many shares does Samantha sell? How much does she receive per share? What does the order book look like after her order is processed? What is her total profit? b) How many shares does Nguyen sell? What price(s) does he sell them at? How much does he receive per share? What does the order book look like after his order is processed? What is his total profit? c) Who is happier, Samantha or Nguyen and why? d) Is your answer to c) really correct? Sam bought her shares for less and sold them for more. What if you looked at return on investment instead of total profit