Can someone please help me out on how to show my work with this study guide problem on Managerial Accounting. Thank you

Managerial Accounting Study Guide

Clock Company sells a single product.The company's sales and expenses for a recent month follow:

TOTALPER UNIT

Sales$600,000$40

Less Variable Expenses420,00028

Contribution Margin180,000$12

Less fixed expenses150,000

Net Operating Income$ 30,000

Required:

a)What is the monthly break-even point in units sold and in sales dollars?

b)Without resorting to computations, what is the total contribution margin at the break-even point?