A mixture contains acid and water in the ratio 7 : 5. If 6 liters of water is added to the mixture, the ratio becomes 7 : 8. Find the quantity of acid in the given mixture.

Question: A mixture contains acid and water in the ratio 7 : 5. If 6 liters of water is added to the mixture, the ratio becomes 7 : 8. Find the quantity of acid in the given mixture.

Solution:
Let, the quantity of acid and water be 7x liters and 5x liters respectively

ATQ,
7x/(5x + 6) = 7/8
⇒ 56x = 7(5x + 6)
⇒ 56x = 35x + 42
⇒ 56x - 35x = 42
⇒ 21x = 42
∴ x = 2

So, Quantity of acid = (7 × 2) liters
= 14 liters