I am getting part b,wrong, ALL answers are correct BUT the red circle around $22,300.00

A department of Alpha Co. incurred the following costs for the month of September Vanable costs, and the variable portion of mixed costs. are a function of the number of units of activity: s, coo Activiy level in units Variable costs 510,750 Fixed costs 30,000 Mixed costs 21.200 861 , 950 Total costs During October the activity level was 8,000 units, and the total costs incurred were Required: a. Calculate the variable costs, fixed costs, and mixed costs incurred during October. Variable cost Fixed cost Mixed cost 17.200 S 30,000 S 22,300 b. use the highlow method to calculate the cost formula for mixed cost (Do not round intermediate calculations and round your answers to 2 decimal places.) 22.300 00 0,37 per unit