In a mixture of milk and water, the quantity of milk is 40% more than the quantity of water. If 30% of mixture is taken out and (y-15) and (y+35) litres of milk and water is added into the mixture, then the new ratio of milk and water will be 4:3 respectively. Find out the value of ‘y’ when the total initial quantity of mixture was 3600 litres.

Solution

The total initial quantity of mixture was 3600 litres.

In a mixture of milk and water, the quantity of milk is 40% more than the quantity of water.

Ratio of the initial quantity of milk and water = 140 : 100 = 7:5

initial quantity of milk = 3600 of (7/12) = 2100

initial quantity of water = 3600 of (5/12) = 1500

If 30% of mixture is taken out and (y-15) and (y+35) litres of milk and water is added into the mixture, then the new ratio of milk and water will be 4:3 respectively.

2100 of (100-30)% + (y-15) : 1500 of (100-30)% + (y+35) = 4 : 3

2100 of 70% + (y-15) : 1500 of 70% + (y+35) = 4 : 3

1470 + (y-15) : 1050 + (y+35) = 4 : 3

3[1470 + (y-15)] = 4[1050 + (y+35)]

4410+3y-45 = 4200+4y+140

4y-3y = 4410-45-4200-140

value of ‘y’ = 25