Correct Answer - Option 1 : 36 litres
Calculation:
Let the quantity of milk and water be 6x and 5x litres respectively,
According to the question,
6x/(5x + 12) = 6/7
⇒ 42x = 30x + 72
⇒ 42x - 30x = 72
⇒ 12x = 72
⇒ x = 6
The quantity of milk = 6x = 6 × 6 = 36 litres
the quantity of water = 5x = 5 × 6 = 30 litres
∴ The quantity of milk is 36 litres.