Let's say a company in March produces 15,000 widgets per month. At that volume, their fixed costs are $45,000 and total variable costs are $75,000 for a total cost of $120,000. What is the fixed cost per unit and the variable cost per unit? Then in April, the same company produces 18,000 widgets. What is the total cost for April? Which of the two cost behaviors change? Why did those costs change