What percent of water must be mixed with honey so as to gain 20% by selling the mixture at the cost price of honey?
Answer & explanation
Answer: (a) 20%
Selling at the honey’s cost price and still gaining 20% means 120 litres of mixture must be sold for what 100 litres of honey cost. So 20 litres of water go into every 100 litres of honey, i.e. 20% of the honey.
- Take 100 litres of honey at ₹1 per litre: cost = ₹100.
- A 20% gain means sales must bring ₹120; at ₹1 per litre that is 120 litres of mixture.
- Water added = 120 − 100 = 20 litres, which is 20% of the honey.
- Check: water is 20/120 = 16.67% of the mixture, which is not an option, so the question means water as a percentage of honey.
Remember · When free water is sold at the price of the pure item, the gain percent equals water as a percent of the pure item.
Question and answer: UPSC's official GS Paper II (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·