7-23 Flexible-budget preparation and analysis. Dartford Enterprises Ltd manufactures just one product line of scientific calculators for engineers. The current standard cost of one unit of the product is as follows: Selling price 10.50 Direct labor (15 minutes) 2.30 Direct materials (2 meters) 1.50 3.80 Contribution 6.70 3.30 Fixed costs (based on the budgeted monthly output of 20,000 units) Operating income 3.40 During last month, due to an unexpected fall in demand for the product, only 15,000 units were made and sold. The actual results for last month were as follows: Sales revenue 153.900 Less: Direct labor (4,000 hours) 35,040 Direct materials (32,000 meters) 23,360 58,400 Contribution 95,500 Fixed costs 67,350 Operating income 28.150 Required 1. Prepare a static-budget-based variance analysis of last month's performance. 2. Prepare a flexible-budget-based variance analysis of last month's performance. 3. Which department manager(s) contributed the most to the success or failure of the budget during the month? Explain your