BE 21-4 Analyzing income under absorption and variable costing

 Variable manufacturing costs are $90 per unit, and fixed manufacturing costs are $270,000. Sales are estimated to be 30,000 units. 

a. How much would absorption costing operating income differ between a plan to produce 30,000 units and a plan to produce 36,000 units? 

b. How much would variable costing operating income differ between the two production plans?