In what ratio should milk and water be mixed so that after selling the mixture at the cost price a profit of 50/3 % is made?

• A. 1:2
• B. 2:5
• C. 2:3
• D. 6:1

Answer: (D)

Method 1 to solve the equation.Let us assume Cost Price (C.P) of 1 liter milk be Y rupees.According to question,Selling Price (S.P) of 1 liter of mixture Y rupees. (Selling price should be same as Cost price)Profit = 50/3 %Let us assume Cost price of 1 Liter of Mixture of Water and Milk = CCost price of 1 Liter of Mixture of Water and Milk = Selling price of Mixture - Profit C = Y - C x 50/3%? C = Y - C x 50/3x100? C = Y - C x 1/3x2? C = Y - C/6? Y = C + C/6? Y = (6C + C)/6? Y = (6C + C)/6? Y = 7C/6? C = 6Y/7Since in Y rupees we will get 1 liter milk.Hence in 1 rupees we will get 1/Y liter milk.Hence in 6Y/7 rupees we will get 1 x 6Y/7 x Y liter milk.Hence in 6Y/7 rupees we will get 6/7 liter milk.We need 1 liter mixture of milk and water for sold on the same price, we need to mix the water.So water quantity in mixture = 1 - 6/7 = 1/7Ratio of Milk and water in mixture = quantity of Milk in Mixture/quantity of Water in MixtureRatio of Milk and water in mixture = 6/7 / 1/7Ratio of Milk and water in mixture = 6 x 7 / 7 Ratio of Milk and water in mixture = 6 / 1Ratio of Milk and water in mixture = 6 : 1Method 2 to solve the question.Let the original amount of milk be 1 liter and the cost price is 1 rupees per liter.Cost price of milk = 1 rupees.Selling price of Mixture = 1 rupees. When the milk is mix with x liters of water milk remaining is 1- x.Let us assume the cost price of milk in mixture is Y and given that the Sold Price is 1.we should use the Profit formula in algebra,Y + Y x 50/3 % = 1 Y + Y x 50/3 x 100 = 1Y + Y x /3 x 2 = 17Y/6 = 1Y = 6/7Y = 6/7 is the cost price of Mixture for 1 liter. Since water is free so there is not cost of water in mixture. So price of milk is 6/7 rs in mixture.Since as per question,In 1 rupees we will get 1 liter of milk.hence in 6/7 rupees we will get 1 x 6/7 = 6/7 liter of milk.Now we have to make 1 liter of mixture with water and milk.quantity of Water + Quantity of Milk = 1 literquantity of Water + 6/7 = 1 quantity of Water = 1 - 6/7 = (7 - 6)/7 quantity of Water = 1/7 Ratio of milk and Water = Quantity of Milk / quantity of Water Ratio of milk and Water = (6/7) / (1/7)Ratio of milk and Water = (6/7) x (7/1)Ratio of milk and Water = 6 x 7/ 7 x 1Ratio of milk and Water = 6 :1