The materials specifications for product A show that one completed unit is made from the following raw materials: Standard composition for one completed product: Material J 2 k g @ 2.00 per kg = 4.00 Material K 2 kg @ 3.00 per kg = 6.00 Material L 4 kg @ 1.50 per kg = 6.00 Materials purchased and issued to produce 100 units of product A: Material J 210 kg @ 1.90 per kg Material K 205 kg @ 2.80 per kg Material L 395 kg @ 1.60 per kg Required Calculate the following variances in respect of materials: (a) Mix variance (5 marks) (b) Yield variance