A restaurant has two appetizer specials. Tomato bread costs $5.50, and stuffed mushrooms cost $6.75. The total amount in sales from the two appetizers on a Friday night was $186.75. Which equation can be used to represent x, the number of stuffed mushroom orders and y, the number of tomato bread orders?
5.5x + 6.75y = 186.75
6.5x + 5.75y = 186.75
6.5x + 5.5y = 186.75
6.75x + 5.5y = 186.75