A shopkeeper sells an article at ₹40 and gets X% profit. However, when he sells it at ₹20, he faces same percentage of loss. What is the original cost of the article?
Answer & explanation
Answer: (c) ₹30
An equal percentage profit and loss on the same cost means the two selling prices lie equally far above and below the cost. The cost is the average of ₹40 and ₹20, i.e. ₹30 (profit and loss both 33⅓%).
- Let the cost be C. Then 40 = C(1 + X/100) and 20 = C(1 − X/100).
- Adding the two: 60 = 2C, so C = ₹30.
- Check: ₹40 is 33⅓% above ₹30, and ₹20 is 33⅓% below it.
Remember · Same percentage profit and loss on one cost price: the cost is the average of the two selling prices.
Question and answer: UPSC's official GS Paper II (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·