Ratio of milk and water = 2 : 1 Quantity of milk = 60 X 2/3 = 40 litre Quantity of water = 20 litre To make ratio, 1: 2, we have to double the water that of milk So, water should be 80 litre. That means 80 ? 20 = 60 litre water to be added.
Alligation or Mixture problems
640 ml of a mixture contains milk and water in ratio 6:2. How much of the water is to be added to get a new mixture containing half milk and half water?
Here total parts of milk and water in the solution is 6+2 = 8 parts. 1part = 640/8 = 80 old mixture contains 6parts of milk and 2 parts of water(6:2). To get new mixture containing half milk and half water, add 4parts of water to the old mixture then 6:(2+4) to make the ratio same. i.e, 4 x 80 = 320 ml.