trouble with a problem. Revenue $480,000 direct material cost 50,000, direct labor cost 300,000, overhead cost 150,000 and operating income (20,000). Pool supervision estimated overhead60,000, cost driver is direct labor cost. the per unit is 15%. I need to compute the operating income for this using the activity based overhead rate. I thought the calculation was 300,000 x 15 for 45,000. but fellow students say the answer is 22,500. I would like to know how they arrived at the answer.