Answer:
64% it's the contribution margin of the company.
Explanation:
To find the contribution margin we need to find the gross profit which is the total sales minus the variable cost of goods, te contribution margin doesn't include the fixed costs only the variable ones.
Income Statement    
Quantities                    400      600              750           1.000  
Sales                      $148,000   $222,000   $277,500   $370,000  
Cost of goods sold     -$54,000  -$81,000         -$101,250  -$135,000  
Contribution Margin  $94,000  $141,000    $176,250   $235,000  
                                        64%       64%                 64%             64%
Fixed Cost                -$60,000  -$60,000   -$60,000  -$60,000  
Total Cost                 -$114,000  -$141,000      -$161,250  -$195,000  
Operating Income          $34,000    $81,000    $116,250   $175,000