Half of the volume of milk and water mixture of ratio 7 : 5 is converted into a mixture of ratio 3 : 1 by the substitution (or replacement) method. The mixture of ratio 7: 5 was formed from the mixture 7: 3 by adding the water in it. If 240L milk is required in the replacement method. What is the total amount of water was added to prepare the mixtue of 7 : 5?

Let the volume of milk and water in the mixture be '7x' and '5x' Total volume = 12x It is given, half of the volume is converted into 3:1 Half = 6x Milk = 3.5x water = 2.5x Later, it is converted into 3:1 milk = 4.5x water = 0.5x Quantity of milk is increased by 'x' It is given that 240L milk is used in replacement process, i.e. 240 - 7(240)/12 = x x = 100 Amount of milk and water in the mixture is 700L and 500L , respectively. 7:3 is converted to 7:5 by adding water water added = 500 - 300 = 200L Hope this helps!