Answer and Explanation:
The computation is shown below;
Particulars                   Sell     process further  
sales                       $450,000      $1,209,000  
Relevant cost    
Process further cost $0               $290,000
Less: Total relevant cost  $0      $290,000  
Income                     $450,000      $629,000
Incremental income                          $179,000
The $1,372,000 is come from
= 5,800 units × $105 + 12,000 units × $50
= $609,000 + $600,000
= $1,209,000
Hence, the company should process further