Implied and actual transaction cost in dollars

Question

You find that the bid and ask prices for a stock are $11.75 and $12.50, respectively. If you purchase or sell the stock, you must pay a flat commission of $15. If you buy 200 shares of the stock and immediately sell them,

Required:

Question: What is your total implied and actual transaction cost in dollars?

• $15
• $180
• $165
• $30

Note: Please show how you came up with the solution.