please show proper working and all steps

4. The Mobile Shoe Company's weekly fixed costs (rent, utilities, etc.) have just increased to $42,000. Their variable costs for producing shoes include $5 per pair for raw materials and 1/6 labor hour. Mobile has a labor force of 100 employees, who are paid \$24 per hour of labor and \$27 per hour for overtime (more than 40 hours per week). a) Suppose that Mobile sells shoes for $12 per pair. What is their break-even point? b) Suppose that Mobile sells shoes for $10 per pair. What is their break-even point? c) What is the break-even point if overtime labor costs $30 instead of $27 per hour