Computing and using the cm ratio

last month when holiday creations, inc., sold 50,000 units, total sales were $200,000, total variable expenses were $120,000, and fixed expenses were $65,000.
required:
1. what is the company's contribution margin (cm) ratio?
2. estimate the change in the company's net operating income if it were to increase its total sales by $1,000.

1. 40%

2. $400

Explanation:

1. The computation of the contribution margin ratio is shown below:

Contribution margin ratio = (Sales - variable expenses) ÷ (sales)

                                          = ($200,000 - $120,000) ÷ ($200,000)

                                          = ($80,000) ÷ ($200,000)

                                          = 40%

2. And, if the total sales is increased by $1,000, so the change in the net income would be

= Increased amount of total sales × contribution margin ratio

= $1,000 × 40%

= $400

answer; i believe the correct answer is (4.0);