Correct Answer - Option 4 : 4 litres
Given:
The capacity of bottle = 80 litres
Initially, the ratio of alcohol and spirit is 7 ∶ 3
In addition, to spirit, the ratio become 2 ∶ 1
Calculation:
Quantity of alcohol in bottle = \(80 × {7 \ \over 10}\)= 56 liters
Quantity of spirit in bottle = 80 - 56 = 24 liters
Now, let 'x' litres of the spirit be added
∴ \( {56 \ \over 24\; + \;x} = {2 \ \over 1}\)
⇒ 56 = 2 × (24 + x)
⇒ 56 = 48 + 2x
⇒ 2x = 8
⇒ x = 4
∴ 4 liters of spirit is added.
