Alligation or Mixture problems
A milkman has 20 liters of milk. If he mixes 5 liters of water, which is freely available, in 20 liters of pure milk. If the cost of pure milk is Rs. 18 per litre, then the profit of the milkman, when he sells all the mixture at cost price, the profit %?
Water in 60 gm mixture=60 x 75/100 = 45 gm. and Milk = 15 gm. After adding 15 gm. of water in mixture, total water = 45 + 15 = 60 gm and weight of a mixture = 60 + 15 = 75 gm. So % of water = 100 x 60/75 = 80%.
Let the price per kg of mixed variety be Rs. P; then By the rule of alligation,Now, (20 - P) / (P - 15) = (2 / 3) ? 60 ? 3P = 2P ? 30 ? 5P = 90 ? P = Rs. 18