A milk merchant buys 50 litres of milk at the rate of Rs. 40 per litre and mixes 5 litres of water in it. If he sells this mixture at the r…

Cost price of the milk = 50 × 40 = Rs. 2000

Given: 5 L water is mixed

Total amount of mixture = 50 + 5 = 55 L

Selling price of mixture = 55 × 42 = Rs. 2310

Profit = Rs. (2310 - 2000) = Rs. 310

∴ Profit % = (310/2000) × 100 = 15.5%