Answer:
Contribution Margin is $32.00.
Explanation:
Average book Price = Â Â Â Â Â Â Â Â Â $40.00
Less: Variable cost:
Selling expenses        $3.00
Administrative expenses $5.00 Â Â Â Â Â Â Â Â Â Â Â ( 40 x 5% )
Total Variable                $8.00
Contribution Margin           $32.00
Contribution Margin % = $32 / 40 = 0.80 = 80%