Answer:
Variable cost per unit = $64 per unit
so correct option is b. $64
Explanation:
given data
sold Arks = 14,000 units
sold Bins = 56,000 units
products    unit selling price   unit variable cost    unit contibution      Â
Arks        $120                 $80                $40
Bins          80                  60                 20
to find out
Carter Co.'s variable cost
solution
we get here Variable cost per unit find as
Variable cost per unit = ( Arks unit variable cost ×  sold Arks + Bins unit variable cost ×  sold Bins )  ÷ total sales
Variable cost per unit = [tex]\frac{(80*14000)+(60*56000)}{14000+56000}[/tex]
Variable cost per unit = $64 per unit
so correct option is b. $64