Saved 4 Derby Phones is considering the introduction of a new model of headphones with the following price and cost characteristics Sales price Variable costs Fixed costs $ 325 per unit 125 per unit 480,000 per month 20 points 015631 Required: a. What number must Derby sell per month to break even? b. What number must Derby sell to make an operating profit of $200,000 for the month? a Break-even sales in units b Number of units to be sold