Can you show me a step by step process on how to answer this question. Im studying for an exam and i need to know exactly how to get this done

4 (Similar to Exercise 6-4) Last month when Global Infrastructure Inc., sold 35,000 units, total sales were $210,000, total variable expenses were $93,750 and fixed expenses were $82,000. 1. What is the company's contribution margin (CM) ratio? 2. What is the estimated change in the company's net operating income if it can increase sales volume by 2,000 units and total sales by $12,000