Company represents a monthly operating income statement to a potential investors Operating income statement of ABC, May 2017 Units sold 10,000 Revenues $100,000 Variable manufacturing costs $55,000 Fixed manufacturing costs 20,000 Total $75,000 Gross margin $25,000 Operating costs Variable marketing costs Fixed marketing and admin costs Total operating costs $5,000 $10,000 $15,000 Operating income $10,000 . How many units must be sold in order to reach (a) a target operating income of $20,000 before tax (b) a target net profit of $20,000 after tax