Part A: Fixed and Variable Cost Stuart Manufacturing produces metal picture frames. The company's income statements for the last two years are given below: Last year This year Units sold........ 50.000 70.000 Sales...... $800,000 $1,120,000 Cost of goods sold. 550,000 710.000 Gross margin 250,000 410,000 Selling and administrative expense. 150,000 190.000 Net operating income. $100,000 $220,000 The company has no beginning or ending inventories. Required: a. Estimate the company's total variable cost per unit and its total fixed costs per year. (Remember that this is a manufacturing firm.) b. Compute the company's contribution margin for this year.