An income statement for Bob's Bookstore for the first quarter of the year is presented below: Bob's Bookstore Income Statement For Quarter Ended March 31 Sales $ 880,000 Cost of goods sold 550,000 Gross margin 330,000 Selling and administrative expenses Selling $ 117,000 Administration 138,000 255,000 Net operating income $ 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. The cost formula for selling and administrative expenses with "X" equal to the number of books sold is: