Oil equal to 20% of the weight of ground nut is extracted in a mill. The matter left after extraction is sold as cattle feed at the rate of Rs 12.5/kg. The groundnuts are bought at Rs 20/kg. The processing cost is Rs 5/kg. At what price (Rs per kg) should the oil be sold to earn 20% profit on total costs (Total cost = Cost of groundnuts and Processing costs)?
Allegation is best approach to solve such kind of Questions 20% Oil = 1/5 Apply allegation 5 = Total 1 = Oil 4 =Left matter He want earn 20% profit on total Total = 20 + 5 = 25 × 6/5 = 30 100 = 70 + 30 100 Rs/kg Oil. 
He want earn 20% profit on total Total = 20 + 5 = 25 × 6/5 = 30 100 = 70 + 30 100 Rs/kg Oil.
