a. What number must Derby sell per month to break even?

Derby Phones is considering the introduction of a new model of headphones with the following price and cost characteristics:

Sales price	$	335	per unit
Variable costs		75	per unit
Fixed costs		728,000	per month

a. What number must Derby sell per month to break even?

b. What number must Derby sell to make an operating profit of $312,000 for the month?