Answer:
<u><em>Part a </em></u>
<u>Belmain Co.</u>
<u>Estimated Income statement for the year ended 2017.</u>
Sales ($240 x 12,000)                                                               $2,880,000
<u>Less Variable Costs :</u>
Direct Materials ($50.00 x 12,000)                                           ($600,000)
Direct Labor ($30.00 x 12,000)                                                 ($360,000)
Factory Overheads ($6.00 x 12,000)                                          ($72,000)
Sales Salaries and Commissions ( $4.00 x 12,000)                  ($48,000)
Miscellaneous selling expenses ( $1.00 x 12,000)                     ($12,000)
Supplies ($4.00 x 12,000)                                                           ($48,000)
Miscellaneous administrative expenses ($1.00 x 12,000)         ($12,000)
Contribution                                                                               $1,728,000
<u>Less Fixed Expenses :</u>
Factory overhead                                                                     ($350,000)
Sales salaries and commissions                                             ($340,000)
Advertising                                                                                 ($116,000)
Travel                                                                                            ($4,000)
Miscellaneous selling expense                                                   ($2,300)
Office and officers’ salaries                                                    ($325,000)
Supplies                                                                                        ($6,000)
Miscellaneous administrative expense                                      ($8,700) 
Net Income ( Loss)                                                                     $576,000
<u><em>Part b</em></u>
0.6 or 60 %
<u><em>Part c</em></u>
Break-even sales (units) = 8,000
Break-even sales (dollars) = $1,920,000
<u><em>Part d</em></u> 
<em>See attachment </em>
<u><em>Part e</em></u>
Margin of safety in dollars  =    $960,000
Margin of safety in percentage  =  33.3 %
<em><u>Part f</u></em>
Operating Leverage = 3.00
Explanation:
<u>Income Statement :</u>
<em>Sales - Expenses = Income</em>
Note : I have separated Variable and Fixed Expenses 
<u>Contribution Margin ratio :</u>
<em>Contribution Margin ratio = Contribution ÷ Sales</em>
                                           =  $1,728,000  ÷  $2,880,000
                                           = 0.6 or 60 %
<u>Break-even sales ( units and dollars) :</u>
<em>Break-even sales (units) = Fixed Costs ÷ Contribution per unit</em>
                                         = $1,152,000 ÷ $144.00
                                         = 8,000
<em>Break-even sales (dollars) = Fixed Costs ÷ Contribution margin ratio</em>
                                             = $1,152,000 ÷ 0.60
                                             = $1,920,000
<u>Margin of safety in dollars and as a percentage of sales :</u>
<u />
<em>Margin of safety in dollars  = Expected Sales (dollars) - Break-even sales (dollars)</em>
                                              =  $2,880,000 - $1,920,000
                                              =   $960,000
<em>Margin of safety in %       = (Expected Sales  - Break-even sales ) ÷ Expected Sales</em>
                                              = $960,000 ÷ $2,880,000
                                              = 33.3 %
<u>Operating leverage</u>
<em>Operating Leverage = Contribution ÷ Earnings Before Interest and Tax</em>
                                   =  $1,728,000 ÷ $576,000
                                   = 3.00