Calculation of Profit

To calculate the profit in this scenario, we need to first determine the cost of the mixture and the selling price of the mixture.

Cost of Mixture

The milkman buys milk at Rs 10 per litre. After adding one-third of water, the milkman has 4 litres of mixture (3 litres of milk + 1 litre of water). Thus, the cost of 4 litres of mixture is:

Cost of 3 litres of milk = Rs 10 x 3 = Rs 30
Cost of 1 litre of water = Rs 0 (as it is free)
Total cost of 4 litres of mixture = Rs 30 + Rs 0 = Rs 30

Therefore, the cost of 1 litre of mixture is Rs 30/4 = Rs 7.50.

Selling Price of Mixture

The milkman sells the mixture at Rs 11 per litre. Thus, the selling price of 4 litres of mixture is:

Selling price of 4 litres of mixture = Rs 11 x 4 = Rs 44

Therefore, the selling price of 1 litre of mixture is Rs 44/4 = Rs 11.

Profit

Profit is the difference between the selling price and the cost price. Therefore, the profit in this case is:

Profit = Selling price - Cost price = Rs 11 - Rs 7.50 = Rs 3.50

Therefore, the milkman makes a profit of Rs 3.50 per litre of mixture sold.

Explanation

The milkman buys milk at a certain cost and adds water to it to increase the volume of the mixture. He then sells the mixture at a higher price, making a profit in the process. This is a common practice in the food and beverage industry.

In this case, the milkman adds one-third of water to the milk, which means that the milkman dilutes the milk by 25%. This dilution helps the milkman to increase the volume of the mixture and make more profit.

However, it is important to note that diluting the milk reduces its nutritional value and quality. Therefore, it is important for consumers to be aware of such practices and make informed choices.

46.67 %