A department of Alpha Co. incurred the following costs for the month of September. Variable costs and the variable portion of mixed casts, are a function of the number of units of activity Activity level in units Variable costs Fixed costs Mixed costs Total costs 4,500 3.9.675 32.00 15,380 557,055 During October, the activity level was 8.800 units, and the total costs incurred were $68,000 Required: a. Calculate the variablo costs, foxed costs, and mixed costs incurred during October October Variable cost Fored cost Mixed Cou 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.) 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 per unit