The variable 'n' is the number of invitation ordered and $2.50 is the price for one invitation. If we want to print 2 invitation, the expression 'n-2' becomes '2-2=0' which means the company will make 2.50(0) + 4.50 = 0 + 4.50 = $4.50 income (which is the fixed price)
To make profit, the company must receive order more than 2 invitation
Since the first caller can win $100, you add 100 onto the end. After you add 50 for every person who answered incorrectly. X being amount tried/answered incorrectly, and Y being the amount you can win at that given time