For example, assume that when a room is cleaned, a new bottle of shampoo is placed in the bathroom. If the shampoo cost is $1.00 per bottle, it does not matter if 1 room is cleaned or 100 rooms are cleaned, the cost per bottle will still be $1.00. However, the total cost will be $100.00 if 100 rooms are cleaned versus $1.00 if 1 room is cleaned. A mixed cost is where the total cost is comprised of both a fixed and a variable cost