A 40-litre mixture contains 25% alcohol and 75% water. If 10 litres of water are added to the mixture, the percentage of alcohol in the new mixture is:
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Correct answer: C
Explanation
The correct answer is option 3 i.e. 20%.
Amount of alcohol in the initial mixture = 25% of 40
⇒ 40 × 25/100 = 10 litres
Amount of water in the initial mixture = 40 - 10 = 30 litres
Now, 10 litres water is added, new amount of mixture = 50 litres
Required percentage = (10/50) × 100
⇒ 100/5 = 20%