The following data have been extracted from the books of Coke Co. Ltd: Joint products Yield (in lbs) of recovered products per tonne of coal Coke 1,420 Coal tar 120 Benzol 22 Sulphate of ammonia 26 Gas 412 2,000 The price of coal is $80 per tonne. The direct labour and overhead costs to the point of split-off are $40 and $60, respectively, per tonne of coal. Calculate the material, labour and total cost of each product on the basis of weight