Answer the following question:

Jimmy Tires Inc. sells tires to service stations for an average of $45 each. The variable costs of each tire are $30 and monthly fixed manufacturing costs total $15,000. Other monthly fixed costs of the company total $12,000.

a) What is the break-even level in tires?

b) What is the margin of safety assuming sales total $90,000?

c) What is the break-even level in tires assuming variable costs increase by 20 percent?

d) What is the break-even level in tires assuming the sell price goes up by 10 percent, fixed manufacturing costs decline by 10 percent and other fixed costs decline by $150?