In a 80 litre of solution containing milk and water in the ratio 2: 3. How much milk should be added to the solution so that the new ratio becomes 4:1?

Current solution: 80 liters with milk:water = 2:3. If ratio is 2:3, then milk = (2/5) × 80 = 32 liters, water = (3/5) × 80 = 48 liters. Let x liters of milk be added. New ratio = (32+x):48 = 4:1. So (32+x)/48 = 4/1, giving 32+x = 192, x = 160 liters. After adding 160 liters milk: total milk = 192 liters, water = 48 liters, ratio = 192:48 = 4:1. Therefore A (160) is correct.