Got a problem that I need some help with. Im finding it difficult to find what numbers to use to find the answers.

The company has estimated the following costs for producing and selling 15,000 units of its product:

Direct materials = $75,000

Direct Labour = 90,000

Variable Overhead = 45,000

Fixed Overhead = 30,000

Variable selling and administrative expenses = 60,000

Fixed selling and administrative expenses = 40,000

Their income tax rate is 40%

a) Given that the selling price of one unit is $38, how many units would they have to sell in order to break even?

b) At a selling price of $43 per unit, how many units would have to be sold in order to produce a profit of $25,000 before taxes?

c) If 7,500 units were produced and sold, what price would they have to charge in order to produce a profit of $30,000 after taxes?

d) If 9,000 units were produced and sold, what price would they have to charge in order to produce a before-tax profit equal to 30% of sales?

For a), they give you the variable cost per unit of $18, which means the unit contribution margin is $20, but im not sure how to find that and I need to show my work, but my answer for the number of units to be sold to break even is 3,500 (fixed costs divided by unit contribution margin)

Any help would be great. Thanks