Final answer:
The contribution margin per unit for a bottle of nail polish sold by Nail Glow, Inc. is $2.75, which is calculated by subtracting the total variable costs per unit of $3.15 from the selling price of $5.90.
Step-by-step explanation:
To calculate the contribution margin per unit for a bottle of nail polish sold by Nail Glow, Inc., we subtract the total variable costs per unit from the selling price per unit. The sale price per unit is $5.90.
The variable costs sum up as follows: $0.86 for the acrylic base, $1.15 for the bottle, $0.57 for pigments, $0.14 for selling commission, and $0.43 for other ingredients, totaling $3.15. Therefore, the contribution margin per unit is $5.90 - $3.15 = $2.75.