30. Iron Decor manufactures decorative iron rallings. In preparing for next year's operatlons, management has developed the following estimates: Total Per Unit Direct materials..S200,000 $10.00 Direct labor (variable). Manufacturing overhead: S50,000 $2.50 Selling & administrative: Va S100,000 $5.00 Required: (5 Points) Compute the following items: a. Unit contribution margin. b. Contribution margin ratio. c. Break-even in dollar sales d. Margin of safety percentage. e. If the sales volume increases by 20% with no change in total fixed expenses, what will be the change in net operating income