A sample of milk from a vessel contains 4% water. What quantity of pure milk should be added to 8 L of milk in the vessel to reduce the water content to 2%?

Correct option is A

Given:

Current volume = 8 L

Water content = 4%

Milk content = 96% of 8 L = 7.68 L

Final water content = 2%

Concept Used:
Adding pure milk does not change the amount of water.

Solution:

Let the quantity of pure milk to be added = x L

4% of 8 L = 0.32 L

Now,

​$$\frac{0.32}{8 + x} = \frac{2}{100}$$​​

​$$0.32 \times 100 = 2 \times (8 + x)$$​​

32 = 16 + 2x

2x = 16

x = 8

Thus, 8 L of pure milk should be added

Alternate Solution:    

49 - 24 = 25

​$$\frac{8}{25}\times 25 = 8 L$$​​