For Quarter Ended March 31 Sales $950,000 Cost of goods sold 660,000 Gross margin 290,000 Selling and administrative expenses Selling $106,000 Administration 116,000 222,000 Net operating income $ 68,000 On average, a book sets for $50. Variable selling expenses are 5 per book with the remaining seling expenses being feed. The variable administrative expenses are 5% of sales with the remainder being fired The cost formula for selling and administrative expenses with "X" equal to the number of books sold is Multiple Choice Y - 515,500 56.5OX 216 Y = $98.500 + $6.50X