Question Petra Comp. senior management wants to develop a budgeting system that motivates managers and other workers to work toward the corporate goals. Petra has incurred the following costs to make 100,000 units during the month of September. Materials $400,000 Direct labor 100,000 Variable manufacturing overhead 20,000 Variable selling and administrative costs 80,000 Fixed manufacturing overhead 200,000 Fixed selling and administrative costs 300,000 Petra's September 1 inventory consisted of 10,000 units valued at $72,000 using absorption costing. Total fixed costs and variable costs per unit have not changed during the past few months. In September, Petra sold 106,000 units at $12 per unit. Required: 1) Using absorption costing, calculate the following. a. Petra's September manufacturing cost per unit b. Petra's September 30 inventory value c. Petra's September net income 2) Using variable costing, calculate the following. a. Petra's September manufacturing cost per unit b. Petra's September 30 inventory value c. Petra's September net income 3) Identify and explain one reason why the income calculated in the previous two questions might differ