Portia Company is a retailer of hammers. Portia pays $3.95 for each hammer and sells them for $8.10. Monthly fixed costs are $25,315. The hammer cost is the only variable cost. a. What is the contribution margin per unit? (Round your answer to 2 decimal places.) b. What is the break-even point in units? (Do not round intermediate calculations.) c. How many units will Portia need to sell to earn target profit of $27,390? (Do not round intermediate calculations.)