The ratio of Acid and Water in a mixture of 25 liters is 4 : 1.  3 liters water is added to the mixture. What will be the ratio of acid and water if further 9 liters of acid is also added?

29 : 8

Total mixture = 25 liters

Ratio of Acid : Water = 4 : 1

So,

• Acid $= \frac{4}{5} \times 25 = 20\text{ L}$
• Water $= \frac{1}{5} \times 25 = 5\text{ L}$

After adding 3 L water:

• Acid $= 20\text{ L}$
• Water $= 5 + 3 = 8\text{ L}$

Now add 9 L acid:

• Acid $= 20 + 9 = 29\text{ L}$
• Water $= 8\text{ L}$

Therefore, the new ratio of Acid : Water is: $29 : 8$