Answer:
Differential revenue from further processing:
= $11.80.
Explanation:
a) Data and Calculations:
Cost of production of an unfinished desk = $35.65
Selling price of an unfinished desk = $64.20
Selling price of a finished desk = $76.00
Additional processing cost = $6.15
Revenue per finished desk    $76.00
Revenue per unfinished desk 64.20
Differential revenue                $11.80
Differential cost per desk:
Cost of unfinished desk       $35.65
Additional cost for producing   6.15
Differential from further processing $41.80
                                      Unfinished     Finished       Differential
Revenue                          $64.20         $76.00           $11.80
Cost of production          (35.65)           (41.80)             (6.15)
Net income                     $28.55         $34.20            $5.65