7. The standard material cost to produce a tonne of Chemical X is : 300 kg of material A @ Rs 10 per kg 400 kg of materials B @ Rs 5 per kg 500 kg of materials C @ Rs 6 per kg During a period, 100 tones of mixture X were produced from the usage of: . 35 tonnes of materials A at a cost of Rs 9,000 per tonne 42 tonnes of materials B at a cost of Rs 6,000 per tonne 53 tonnes of materials C at a cost of Rs 7,000 per tonne Calculate all variances