(a) The GTR Ltd uses a weighted average process cost system. Data relevant to the month of December is given below. All materials are introduced at the beginning of the process. 800 units 1,000 units 4,200 units Work-in process, 1 December (25% complete for conversion costs) Work-in process, 31 December (20% complete for conversion costs) Units started during December Work-in process as at 1 December. - Materials - Labour cost $ 900 400 132 - Production overheads Resources incurred/added during December: - Materials - Labour hours worked - Production overheads 2,800 kgs 1,000 hours $4,000 GTR Ltd pays $1.5 per kg for the material and $10 per hour to their workers. Required: Prepare the process costing schedules under the weighted average method for the month of December by showing each of the following analysis/elements:- Physical flow in units Equivalent units Unit costs Total costs (10 marks) * Keep to 2 decimal places if applicable. (b) Standard costs are said to be useful in controlling costs. Assume that the standard cost for raw materials per unit of finished product is $6.00 based on 3 kg at $2.00 per kg. (1) Explain how such a standard can be used to evaluate performance. (100-150 words) (4 marks) () Why is the degree of controllability important in utilising standard costs to evaluate performance? (200-250 words) (6 marks)