A department of Delta Company incurred the following costs for the month of June. Variable costs, and the variable portion of mixed costs, are a function of the number of units of activity: During July, the octivify level was 8,400 units, and the fotal costs incured were $68,500 Required: a. Calculate the variable costs, fixed costs, and mixed costs incurred during July. b. Use the high-low method to calculate the cost formuda for mixed cost Complete this question by entering vquer answers in the tabs below. Calculate the variable costs, foxed costs, and mixed costs incuried during July