High–low method A department of Alpha Co. incurred the following costs for the month of September. Variable costs, and the variable portion of mixed costs, are a function of the number of units of activity:

Activity level in units.

5,000

Variable costs

$10,000

Fixed costs

30,000

Mixed costs.

20,000

Total costs.

$60,000

During October the activity level was 8,000 units, and the total costs incurred were $70,500.

Required:

a. Calculate the variable costs, fixed costs, and mixed costs incurred during October.

b. Use the high–low method to calculate the cost formula for mixed cost.