In a 729 litres mixture of milk and water, the ratio of milk to water is 7 :…
2026
In a 729 litres mixture of milk and water, the ratio of milk to water is 7 : 2. to get a new mixture containing milk and water in the ratio 7 : 3, the amount of water to be added is:
- A.
81 litres
- B.
71 litres
- C.
56 litres
- D.
50 litres
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Correct answer: A
Step 1: Find the quantity of milk in the mixture. Milk = (7/9) × 729 = 567 litres.
Step 2: Find the current amount of water. Water = 729 − 567 = 162 litres.
Step 3: Let x litres of water be added and set up the new ratio. We need 567 : (162 + x) = 7 : 3.
Step 4: Solve the equation. 3 × 567 = 7 × (162 + x) ⇒ 1701 = 1134 + 7x ⇒ 7x = 567 ⇒ x = 81.
Answer: 81 litres of water should be added.