A factory has received an order of three different types of casting X, Y and Z, weighing respectively 27, 36 and 45 tonnes. 10% of raw materials used are wasted in manufacturing process and are sold as scrap for 25% of the cost price of raw materials.

The cost of raw materials is Rs. 200 per tonne. The wages for the three types of castings are Rs. 6,000, Rs. 8,000 and Rs. 10,000 respectively. The costs of moulds for the three different types of costings are Rs. 600, Rs. 800 and Rs. 1,000 respectively.

If the factory overhead charges are 50% of the wages in each case, fi nd the cost of production per tonne for each type of casting.