Question

50 ml rum is added to a cocktail containing whiskey and brandy in the ratio 3 ∶ 2. Now, 70 ml of mixture is taken out and 15 ml of rum is added. What is the percentage of whiskey in the final mixture, if the quantity of the cocktail was 300 ml?
1. 52%
2. 55%
3. 35%
4. 39%
5. 49%

Answer 1

Correct Answer - Option 5 : 49%

Quantity of cocktail = 300 ml

Ratio of whisky and brandy = 3 ∶ 2

∴ Quantity of whisky = (3/5) × 300 = 180 ml

Quantity of brandy = (2/5) × 300 = 120 ml

Now, 50 ml of rum is added to cocktail

Quantity of mixture = 300 + 50 = 350 ml

70 ml of mixture is taken out

∴ Quantity of whisky removed = 70 × (180/350) = 36 ml

Quantity of brandy removed = 70 × (120/350) = 24 ml

Quantity of rum removed = 70 × (50/350) = 10 ml

15 ml rum is added to mixture 

Quantity of rum in mixture = 50 – 10 + 15 = 55 ml

Now, Quantity of whisky in mixture = 180 – 36 = 144 ml

Quantity of mixture = 350 – 70 + 15 = 295 ml

∴ Required percentage = (144/295) × 100 = 48.81% ≈ 49%

∴ The percentage of whiskey in the final mixture is 49%