In a mixture, the ratio of milk to water is 7:2. If 9 liters of water are added to it, the ratio becomes 7:5. Find the original quantity of milk.
Show answer & explanation
Correct answer: A
Explanation
Let Milk = 7x, Water = 2x
New amount of water = 2x + 9
New ratio:
7x / (2x + 9) = 7 / 5
7x / (2x + 9) = 7/5
⇒ 5 × 7x = 7(2x + 9)
⇒ 35x = 14x + 63
⇒ 35x − 14x = 63
⇒ 21x = 63
⇒ x = 3
Milk = 7x = 7 × 3 = 21 liters