The following is ABC Corporation's contribution format income statement for last month:

Sales	$1,200,000
Less variable expenses	800,000
Contribution margin	400,000
Less fixed expenses	300,000
Net income	$100,000

The company has no beginning or ending inventories and produced and sold 20,000 units during the month.

Required:
c. If sales increase by 100 units, by how much should net income increase?
d. How many units would the company have to sell to attain target profits of $125,000?
e. What is the company's margin of safety in dollars?