Answer:
Part 1.
Contribution margin income statement for the year.
Sales (4,900 x 340)                                                        1,666,000
<u>Less Variable Costs </u>
Plastic for casing                                        171,500
Wages of assembly workers                   490,000
Drum stands                                              215,600
Sales commissions                                    161,700       (1,038,800)
Contribution                                                                      627,200
<u>Less Fixed Costs</u>
Taxes on factory                                          6,000
Factory maintenance                                 12,000
Factory machinery depreciation               72,000
 Lease of equipment for sales staff           12,000
Accounting staff salaries                           62,000
Administrative management salaries      142,000       (306,000)
Net Income                                                                      321,200
Part 2.
Contribution margin per unit = $627,200 / 4,900  = $128.00
Contribution margin ratio =  $627,200/ $1,666,000 = 37.65 %
Explanation:
The Contribution Margin Income Statement calculates separately the contribution and net income as shown above.