Question: A mixture of two liquids A and B is in the ratio 4:5. If 9 liters of liquid B is added, the ratio becomes 4:6. What was the initial quantity of liquid B?
Options:
Correct Answer: 20 liters
Solution:
Let the initial quantities be 4x and 5x. After adding 9 liters of B, the new ratio is (4x)/(5x + 9) = 4/6. Solving gives x = 3, so initial quantity of B = 5x = 15 liters.