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 5,500 Activity level in units Variable costs Fixed costs Mixed costs Total costs $11,000 31,000 17.300 $59, 300 During October, the activity level was 9,400 units, and the total costs incurred were $69.000 Required: a. Calculate the variable costs, fixed costs, and mixed costs incurred during October October Variable cost Fixed cost Micred cost b. Use the high-low method to calculate the cost formula for mixed cost. (Do not round Intermediate calculations and round your answers to 2 decimal places.) Cost formula