Cost price from a rupee profit — Aptitude Question
Cost price from a rupee profit: A trader marks goods 20% above cost and gives a 10% discount, making a profit of ₹40. Answer and worked solution on CodeKairo.
- Topic: Profit & Loss
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
A trader marks goods 20% above cost and gives a 10% discount, making a profit of ₹40. What was the cost price?
Options
- ₹400
- ₹500
- ₹600
- ₹800
Show the answer and the worked solution
Correct answer: B. ₹500
Worked solution
- Net factor = 1.20 × 0.90 = 1.08, a profit of 8%.
- 8% of CP = 40 → CP = 40 ÷ 0.08 = ₹500.
Answer: ₹500.
The idea
Convert the chain of percentages into a single profit rate, then use the rupee figure to unlock the base. One division at the end.
Shortcut. Test the options: ₹500 is marked up to 600, sells at 540 after 10% off, and yields exactly ₹40 profit.
Common trap. "₹400" — taking the net rate as 20 − 10 = 10%, so CP = 40 ÷ 0.10.