Please show calculation and explanation

Penny manufactures a single product, the Darcy. Budgeted results and actual results for May are as follows. Actual Variance Budget 7,500 8,200 Production and sales of the Darcy (units) Sales revenue Direct materials Direct labour Production overhead Administration overhead $ 75,000 22,500 15,000 22,500 10,000 70,000 5,000 $ 81,000 23,500 15,500 22,800 11,000 72,800 8,200 $ 6,000 (F) 1,000 (A) 500 (A) 300 (A) 1,000 (A) 2,800 (A) 3,200 (F) Profit Note. (F) denotes a favourable variance and (A) an unfavourable or adverse variance. In this example, the variances are meaningless for the purposes of control. All costs were higher than budgeted but the volume of output was also higher; it is to be expected that actual variable costs would be greater those included in the fixed budget. However, it is not possible to tell how much of the increase is due to poor cost control and how much is due to the increase in activity. Similarly, it is not possible to tell how much of the increase in sales revenue is due to the increase in activity. Some of the difference may be due to a difference between budgeted and actual selling price, but we are unable to tell from the analysis above. For control purposes we need to know the answers to questions such as the following. Were actual costs higher than they should have been to produce and sell 8,200 Darcys? Was actual revenue satisfactory from the sale of 8,200 Darcys? Instead of comparing actual results with a fixed budget which is based on a different level of activity to that actually achieved, the correct approach to budgetary control is to compare actual results with a budget which has been flexed to the actual activity level achieved. Suppose that we have the following estimates of the behaviour of Penny's costs: (a) Direct materials and direct labour are variable costs (b) Production overhead is a semi-variable cost, the budgeted cost for an activity level of 10,000 units being $25,000 (c) Administration overhead is a fixed cost (d) Selling prices are constant at all levels of sales