Exercise 4 (20 points) Mathias Corporation manufactures and sells wire rakes. The rakes sell for $20 each. Information about the company's costs is as follows: Variable manufacturing cost per unit.... Variable selling and administrative cost per unit. Fixed manufacturing overhead per month. Fixed selling and administrative cost per month. $9 $4 $250,000 $350,000 a. Determine the company's monthly break-even point in units. b. Determine the sales volume (in dollars) required for a monthly operating income of $100,000. c. Estimate the amount by which monthly operating income will increase if the company anticipates a $200,000 increase in monthly sales volume.