CDS Mathematics · Teaching notes
Percentage, Profit and Loss — CDS Elementary Mathematics
Percentage, Profit and Loss has 50 past-year questions in CDS Elementary Mathematics, in 20 of the twenty-one sittings from 2016 (II) to 2026 (II). Profit and loss alone accounts for 17 of them, only three are HARD, and nearly every wrong option comes from dividing by the wrong base or adding percentages that should be multiplied. The pages go from percentages of a quantity to successive changes, then to profit and loss, and end with discounts.
Every subtopic, worked example, formula and trap in one printable document — answers shown, ready to share.
Subtopic notes
Percentages of a Quantity
14 PYQsA percentage is a fraction with denominator 100; every question turns on which quantity is the base, the 100%.
Successive Percentage Change
12 PYQsTwo percentage changes combine by multiplying their factors, never by adding the percentages.
Profit and Loss
17 PYQsProfit and loss are percentages of the cost price: SP = CP × (1 + p/100) for a profit of p%.
Discounts and Marked Price
7 PYQsA discount is a percentage of the marked price; successive discounts multiply, and profit is still measured on the cost.
Formula & revision sheet
7 formulas · 10 gotchas across all subtopics — the exam-eve cheat-sheet
Formula & revision sheet
7 formulas · 10 gotchas across all subtopics — the exam-eve cheat-sheet
Watch out for (2)
- The square root of a percentage→ Percentage of a base
- 20% more does not reverse to 20% less→ More than and less than
Watch out for (3)
- Percentages do not add→ Multiplying the factors
- Increased BY versus increased TO→ Multiplying the factors
- Not the same percentage back→ Price against consumption
Formulas (2)
Watch out for (3)
- Profit is a percentage of COST→ Cost price, selling price and the two-scenario trick
- The new cost is the new base→ Cost price, selling price and the two-scenario trick
- Divide by the smaller count→ Profit hidden in quantities
Watch out for (2)
- Discounts do not add→ Marked price, discount and profit
- Two bases in one question→ Marked price, discount and profit
PYQ weightage by concept
7 concepts · 50 PYQs — where the marks actually sit, so you know what to drill first
PYQ weightage by concept
7 concepts · 50 PYQs — where the marks actually sit, so you know what to drill first
| Concept | PYQs | Share |
|---|---|---|
| Percentage of a base | 11 | 22% |
| More than and less than | 3 | 6% |
| Concept | PYQs | Share |
|---|---|---|
| Multiplying the factors | 7 | 14% |
| Price against consumption | 5 | 10% |
| Concept | PYQs | Share |
|---|---|---|
| Cost price, selling price and the two-scenario trick | 12 | 24% |
| Profit hidden in quantities | 5 | 10% |
Test yourself on Percentage, Profit and Loss
15 past CDS questions from this chapter, timed at 18 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.