How many liters of water should be added to a 30 liters mixture of milk and water containing milk and water in the ratio 7 : 3 such that the resultant mixture has 40% water in it?

Name: How many liters of water should be added to a 30 liters mixture of milk and water containing milk and water in the ratio 7 : 3 such that the resultant mixture has 40% water in it?
Uploaded: 2025-11-18T18:07:58.603533+05:30
Duration: 5 min 53 s
Description: How many liters of water should be added to a 30 liters mixture of milk and water containing milk and water in the ratio 7 : 3 such that the resultant mixture has 40% water in it?

Solution

30 litres of a mixture of milk and water contains milk and water in the ratio 7:3. Therefore, the amount of milk = 21 litres and the amount of water = 9 litres in the solution.

Let us assume we added 'x' litres of water. Now, we want the resultant solution to have 40% water in it.

$$9+x=\dfrac{40}{100}\times\left(30+x\right)$$

$$45+5x=60+2x$$

$$3x=15$$

$$x=5$$

Thus, 5 litres of water must be added.