Raw materials Rs. 35,250 Add: Carriage on purchases 850 3 ,100 Direct wages 18,450 (a) Prime cost 54,550 vactory overhead 2,750 57,300 Less: Sale of factory Ex: Cement, Steel, Sugar, paper, brick works, quarries, breweries, dairies etc. Cost units are a tonne of cement or steel or sugar, 1000 bricks, a barrel of beer, a gallon of milk etc. Cost sheet is prepared to ascertain cost of products.