An income statement for Sam's Bookstore for the first quarter of the year is presented below: Sam's Bookstore Income Statement For Quarter Ended March 31 Sales Cost of goods sold Gross margin Selling and administrative expenses Selling Administration Net operating income. $117,000 138,000 $880,000 550,000 330,000 The contribution margin for Sam's Bookstore for the first quarter is: 255,000 $ 75,000 On average, a book sells for $55. Variable selling expenses are $5 per book with the remaining selling expenses being fixed. The variable administrative expenses are 4% of sales with the remainder being fixed.