Expenses can be classified into two categories, fixed and variable Expenses. Since these expense behave differently based on the level of sales volumes, assume we identify certs costs along with number of annual units sold of 100 if we owned a restaurant.

Item: Raw Materials (cost for hamburgers)
Total Annual Cost: 650
Item : Building Rent
total Annual Cost: 9000

Identify which cost item above is fixed and variable and why? What is the cost per unit of each? If the sales volume is increased to 6000 units and then to 8000 units the following year(and are still within the relevant range), what would be the total annual cost and unit cost of fixed and variable costs? Please detailed calculation for each requirement.