Colorado Business Tools manufactures calculators. Costs incurred in making 9,620 calculators in February included $29,150 of fixed manufacturing overhead. The total absorption cost per calculator was $9.77 Required: a. Calculate the variable cost per calculator (Do not round intermediate calculations. Round your answer to 2 decimal places.) Variable cost per calculator b. The ending inventory of calculators was 880 units higher at the end of the month than at the beginning of the month. By how much and in what direction (higher or lower) would operating income for the month of February be different under variable costing than under absorption costing? (Do not round intermediate calculations.) Operating income under variable costing will be c. Express the calculator cost in a cost formula (Do not round intermediate calculations. Round "Variable cost" to 2 decimal places.) Total cost