Percentage is a foundational topic in the Quantitative Aptitude section of the IBPS PO exam. It plays a crucial role not just in standalone percentage-based questions, but also in topics like Data Interpretation, Profit & Loss, Simple & Compound Interest, and Time & Work. A strong grasp of percentage calculations can help candidates solve 10-15 questions quickly, saving crucial time for tougher problems. Percentage is not just a topic; it is a skill.
Percentage for IBPS PO 2025
A percentage is a way of expressing a number as a fraction of 100. It is denoted using the symbol “%”. For example, 40% means 40 out of 100. For IBPS PO 2025, a strong command over percentages can drastically improve your performance across the entire Quant section. To excel, candidates must move beyond basic formulas and focus on real-exam scenarios like successive discounts, population growth, and percentage change in ratios. The formula to convert percentages is:
Percentage = (Part / Whole) × 100
Value = (Percentage × Total) / 100
These basic concepts are the building blocks for solving more advanced quantitative problems.
Section 1: Core Percentage Concepts
| Concept | Formula | Example |
| Percentage Increase/Decrease | (Change/Original) × 100 | If price rises from ₹80 to ₹100, increase = (20/80)×100 = 25% |
| Fraction ↔ Percentage | 1/4 = 25%, 1/8 = 12.5% | Memorise conversions up to 1/20 |
| x% of y = y% of x | x% × y = y% × x | 28% of 50 = 50% of 28 = 14 |
| Net Percentage Change | a + b + (a×b)/100 | Successive changes of +20% & -15% = 20 – 15 – (20×15)/100 = 2% |
Section 2: Application of Percentage in IBPS PO Exam
(A) Profit-Loss & Discounts: Key Formulas:
- Profit% = (Profit/CP) × 100
- Selling Price = CP × (1 ± Profit%/100)
- Successive Discounts: Two 20% discounts ≠ 40% off! Use 20 + 20 – (20×20)/100 = 36%.
Example: A shirt marked at ₹800 is sold at two discounts of 15% and 10%. Final price?
Solution:
- First discount: 800 – 15% = ₹680
- Second discount: 680 – 10% = ₹612
- Shortcut: Net discount = 15 + 10 – (15×10)/100 = 23.5% → 800 – 23.5% = ₹612.
(B) Data Interpretation (DI): Common Scenarios:
- Year-on-Year growth rates in sales/production
- Market share percentages
- Percentage contribution to total
- DI Hack: When calculating % share, round off denominators for speed: If total = 4830 ≈ 4800 → 12% of 4800 = 576 (Actual: 12% of 4830 = 579.6).
(C) Interest & Population Growth
- Simple Interest: SI = (P × R × T)/100
- Compound Interest: A = P(1 + R/100)^n
- Population Growth: Similar to CI. If a town’s population grows at 10% annually for 2 years: Final = Initial × (1.10)².
Tricks and Shortcuts to Solve Percentage Questions
To ace this topic quickly, here are some essential tricks and shortcuts:
Use Fraction Equivalents (see table below): It helps save time in calculation-heavy questions.
Always break values into 100-based logic: This helps in visualising and estimating answers faster.
Use smart percentage values for estimation: Know common values like 10%, 20%, 25%, etc.
Apply reverse percentage techniques: Useful when finding the original price/number after an increase/decrease.
Use Approximation: Helpful in Data Interpretation sets where exact values aren’t always needed.
Percentage to Fraction Conversions
Here’s a ready-reference table of percentage to fraction conversions you should memorise:
| Percentage | Fraction | Shortcut Tip |
| 1/1 | 100% | Whole unit |
| 1/2 | 50% | Half |
| 1/3 | 33.33% 33 1/3% | Divide by 3 |
| 1/4 | 25% | Divide by 4 (or half of 50%) |
| 1/5 | 20% | Divide by 5 |
| 1/6 | 16.66% or 16 2/3% | Half of 33.33% |
| 1/7 | ~14.28% or 14 2/7% | Memorise as 14.3% (approx.) |
| 1/8 | 12.5% | Half of 25% |
| 1/9 | 11.11% or 11 1/9% | Repeating decimal |
| 1/10 | 10% | Move the decimal left once |
| 1/11 | ~9.09% or 9 1/11% | Useful for quick approximations |
| 1/12 | 8.33% or 8 1/3% | Half of 16.66% |
| 1/13 | ~7.69% or 7 9/13% | Rare but helpful in DI |
| 1/14 | ~7.14% or 7 1/7% | Half of 14.28% |
| 1/15 | ~6.66% or 6 2/3% | Close to 6.67% |
| 1/16 | 6.25% | Half of 12.5% |
| 1/20 | 5% | Useful for 5% increments |
| 2/3 | 66.66% | Double of 33.33% |
| 3/4 | 75% | 25% × 3 |
| 3/5 | 60% | 20% × 3 |
| 5/6 | ~83.33% or 83 1/3% | 100% – 16.66% |
| 7/8 | 87.5% | 100% – 12.5% |
Common Mistakes to Avoid in Percentage Questions
Even strong candidates make mistakes with percentages due to misinterpretation or rushing through questions. Here are some pitfalls to avoid:
- Confusing increase vs. decrease: An increase of 20% followed by a decrease of 20% doesn’t bring the value back to original.
- Forgetting to calculate on base value: Always apply the percentage to the correct base (e.g., original price, total population).
- Misplacing decimal points: When converting percent to a decimal, divide by 100 carefully.
- Skipping units: Especially important in profit/loss or interest-based questions where units matter.
- Avoid unnecessary calculations: Estimation is often enough for elimination in MCQs.
Practice Strategy for Percentage
- Start with conceptual clarity and basic formulae.
- Memorize all important fraction conversions.
- Practice 10–15 percentage-based problems daily.
- Solve mixed problem sets involving percentages + profit & loss, and time & work.
- Attempt previous year IBPS PO questions and mock tests focusing on DI.
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