"I'll never understand this accounting stuff," Blake Dunn yelled, waving the income statement he had just received from his accountant in the morning mail. "Last month, we sold 2,000 stuffed State University mascots and earned $6,565 in operating income. This month, when we sold 3,000 I thought we'd make $9,848. But this income statement shows an operating income of $11,615! How can I ever make plans if I can't predict my income? I'm going to give Janice one last chance to explain this to me," he declared as he picked up the phone to call Janice Miller, his accountant.

"Will you try to explain this operating income thing to me one more time?" Blake asked Janice. "After I saw last month's income statement, I thought each mascot we sold generated $3.28 in net income; now this month, each one generates $3.87! There was no change in the price we paid for each mascot, so I don't understand how this happened. If I had known I was going to have $11,615 in operating income, I would have looked more seriously at adding to our product line."

Taking a deep breath, Janice replied, "Sure, Blake. I'd be happy to explain how you made so much more operating income than you were expecting."

February March Sales revenue $25,000 $37,500 Cost of goods sold 10,000 15,000 Gross profit 15,000 22,500 Rent expense 1,500 1,500 Wages expense 3,500 5,000 Shipping expense 1,100 1,650 Utilities expense 750 750 Advertising expense 1000 1400 Insurance expense 585 585 Operating income 6516 $11,615Total Per unit Sales 37,500 12.5 Variable costs Cost of goods sold 15,000 5 Wages 4500 1.50 Shipping 1,650 0.55 Advertising 1,200 0.40 Total variable costs 22,350 7.45 Contribution margin 15,150 5.05 Fixed expenses Rent 1,500 Utilities 750 Insurance 585 Wages 500 Advertising 200 Total fixed expenses 3,535 Operating income 11.615