Percentages Shortcut Tricks for Aptitude Tests [With 10 Examples]

"Time is the difference between a good score and a great score."

Every competitive exam—whether it's IBPS PO, SBI Clerk, SSC CGL, RRB NTPC, CAT, or a campus placement test—has one thing in common: Percentage problems.

And here is the truth: You don't need to be a math wizard. You just need shortcut tricks.

In this guide, I will walk you through 10 proven percentage shortcuts that will save you minutes on your aptitude test. No lengthy calculations. No mental fatigue. Just fast, accurate results.

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Why Percentage Shortcuts Matter

A typical aptitude test gives you 60–90 seconds per question. If you solve a percentage problem the "long way" (writing fractions, multiplying decimals), you lose precious time.

But with percentage shortcut tricks, you can solve the same problem in 10–15 seconds.

The Goal: Turn percentage problems into simple mental math.

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The Foundation: Fraction ↔ Percentage Table

You must memorize this table. It is the key to all shortcuts.

Fraction	Percentage	Fraction	Percentage
$\frac{1}{1}$	100%	$\frac{1}{6}$	16.67%
$\frac{1}{2}$	50%	$\frac{1}{7}$	14.28%
$\frac{1}{3}$	33.33%	$\frac{1}{8}$	12.5%
$\frac{1}{4}$	25%	$\frac{1}{9}$	11.11%
$\frac{1}{5}$	20%	$\frac{1}{10}$	10%
$\frac{1}{20}$	5%	$\frac{1}{25}$	4%

Example: If you need 25% of 200, and you know $25\% = \frac{1}{4}$, then $200 \div 4 = 50$. Done.

Now, let's get to the 10 powerful shortcuts.

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Shortcut 1: The Swapping Trick

Formula:

$\boxed{x\% \text{ of } y = y\% \text{ of } x}$

This single trick can turn a difficult calculation into an easy one.

Example 1

Problem: What is 8% of 250?

Long way: $\frac{8}{100} \times 250 = 20$

Shortcut: Swap → 250% of 8 = 2.5 × 8 = 20

Example 2

Problem: What is 12% of 50?

Swap: 50% of 12 = 6

✅ Answer: 6

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Shortcut 2: The 10% / 1% Split Method

Concept: Break any percentage into easy parts: 10%, 1%, 5%, etc.

• 10% of a number = Move decimal one place left
• 1% of a number = Move decimal two places left
• 5% of a number = 10% ÷ 2

Example 3

Problem: Find 23% of 400.

$\begin{aligned} 10\% \text{ of } 400 &= 40 \\ 20\% \text{ of } 400 &= 80 \\ 1\% \text{ of } 400 &= 4 \\ 3\% \text{ of } 400 &= 12 \end{aligned}$

$23\% \text{ of } 400 = 20\% + 3\% = 80 + 12 = 92$

✅ Answer: 92

Example 4

Problem: Find 47% of 500.

$\begin{aligned} 50\% \text{ of } 500 &= 250 \\ 3\% \text{ of } 500 &= 15 \end{aligned}$

$47\% \text{ of } 500 = 50\% - 3\% = 250 - 15 = 235$

✅ Answer: 235

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Shortcut 3: Finding the Whole from a Percentage

Formula:

$\boxed{\text{If } x\% \text{ of a number } = y, \text{ then the number } = \frac{y}{x} \times 100}$

Example 5

Problem: 20% of a number is 30. Find the number.

$\text{Number} = \frac{30}{20} \times 100 = 1.5 \times 100 = 150$

✅ Answer: 150

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Shortcut 4: "More Than / Less Than" Ratio (Exam Favorite)

These are the most commonly asked percentage questions in banking and SSC exams.

Formula 4A: A is R% more than B

$\boxed{\text{B is } \frac{R}{100 + R} \times 100\% \text{ less than A}}$

Formula 4B: A is R% less than B

$\boxed{\text{B is } \frac{R}{100 - R} \times 100\% \text{ more than A}}$

Example 6 (Bank Exam Question)

Problem: Ram's salary is 30% more than Renu's. By what percent is Renu's salary less than Ram's?

Apply Formula 4A ($R = 30$):

$\begin{aligned} &= \frac{30}{100 + 30} \times 100 \\ &= \frac{30}{130} \times 100 \\ &= \frac{3000}{130} \approx 23.07\% \end{aligned}$

✅ Answer: 23.07%

Example 7

Problem: A's salary is 20% less than B's. By what percent is B's salary more than A's?

Apply Formula 4B ($R = 20$):

$\begin{aligned} &= \frac{20}{100 - 20} \times 100 \\ &= \frac{20}{80} \times 100 = 25\% \end{aligned}$

✅ Answer: 25%

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Shortcut 5: Successive Percentage Change

⚠️ Warning: Never add percentages directly for successive changes!

Formula:

$\boxed{\text{Net change} = a + b + \frac{a \times b}{100}}$

Use + for increase, – for decrease

Example 8

Problem: Price increases by 10%, then decreases by 10%. Net change?

$\begin{aligned} \text{Net} &= 10 + (-10) + \frac{10 \times (-10)}{100} \\ &= 0 + \frac{-100}{100} = -1\% \end{aligned}$

✅ Answer: 1% decrease (not zero!)

Example 9

Problem: Salary increased by 20%, then another 10%. Net increase?

$\begin{aligned} \text{Net} &= 20 + 10 + \frac{20 \times 10}{100} \\ &= 30 + 2 = 32\% \end{aligned}$

✅ Answer: 32% increase

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Shortcut 6: Expenditure Constancy (Price ↑ → Consumption ↓)

Scenario: Price changes, but total expenditure remains the same.

Formula: Price increases by R%

$\boxed{\text{Consumption must drop by } \frac{R}{100 + R} \times 100\%}$

Formula: Price decreases by R%

$\boxed{\text{Consumption must increase by } \frac{R}{100 - R} \times 100\%}$

Example 10

Problem: Petrol price rises by 25%. By what percent must consumption reduce to keep bill unchanged?

$\begin{aligned} \text{Reduction} &= \frac{25}{100 + 25} \times 100 \\ &= \frac{25}{125} \times 100 = 20\% \end{aligned}$

✅ Answer: 20% reduction

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Shortcut 7: Population Growth (Compound Interest Style)

Formula:

$\boxed{\text{Population after } n \text{ years} = P \times \left(1 + \frac{R}{100}\right)^n}$

Where:

• $P$ = Present population
• $R$ = Annual growth rate (%)
• $n$ = Number of years

Example

Problem: A town's population is 20,000. It grows at 5% per year. Population after 2 years?

$\begin{aligned} \text{Year 1: } & 20,000 \times 1.05 = 21,000 \\ \text{Year 2: } & 21,000 \times 1.05 = 22,050 \end{aligned}$

✅ Answer: 22,050

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Shortcut 8: Depreciation (Value Decrease)

Formula:

$\boxed{\text{Value after } n \text{ years} = P \times \left(1 - \frac{R}{100}\right)^n}$

Where:

• $P$ = Present value
• $R$ = Annual depreciation rate (%)
• $n$ = Number of years

Example

Problem: A machine worth ₹1,00,000 depreciates 10% yearly. Value after 2 years?

$\begin{aligned} \text{Year 1: } & 1,00,000 \times 0.90 = 90,000 \\ \text{Year 2: } & 90,000 \times 0.90 = 81,000 \end{aligned}$

✅ Answer: ₹81,000

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Shortcut 9: Passing Marks Problems

Scenario: Two students score different percentages. One fails by $X$ marks, the other passes with $Y$ extra marks.

Formula:

$\boxed{\text{Total Marks} = \frac{(X + Y) \times 100}{Q - P}}$

Where:

• $P$ = First student's percentage
• $Q$ = Second student's percentage
• $X$ = Marks first student fell short by
• $Y$ = Marks second student exceeded by

Example

Problem: A scores 30% and fails by 15 marks. B scores 40% and gets 35 marks above passing. Find total marks.

$\begin{aligned} \text{Total} &= \frac{(15 + 35) \times 100}{40 - 30} \\ &= \frac{50 \times 100}{10} = 500 \end{aligned}$

✅ Answer: 500

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Shortcut 10: Election / Voting Percentage

Scenario: Total votes = Valid votes + Invalid votes. Two candidates contest.

Step-by-step method:

1. Find the percentage difference between the two candidates
2. That percentage of valid votes = Winning margin in votes
3. Calculate valid votes, then total votes

Example

Problem: In an election, 10% votes were invalid. Winner got 60% of valid votes and won by 1800 votes. Find total voters.

$\begin{aligned} \text{Loser got} &= 40\% \text{ of valid votes} \\ \text{Difference} &= 60\% - 40\% = 20\% \\ 20\% \text{ of valid votes} &= 1800 \\ \text{Valid votes} &= 1800 \times 5 = 9000 \\ \text{Total votes} &= 9000 \times \frac{100}{90} = 10,000 \end{aligned}$

✅ Answer: 10,000

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Bonus: Quick Reference Card (Save This!)

Problem Type	Shortcut Formula
x% of y	$\boxed{y\% \text{ of } x}$
Net % change (a, b)	$\boxed{a + b + \frac{ab}{100}}$
A is R% > B	B is $\boxed{\frac{R}{100+R} \times 100\%}$ < A
A is R% < B	B is $\boxed{\frac{R}{100-R} \times 100\%}$ > A
Price ↑ R%, keep expense same	Consumption ↓ $\boxed{\frac{R}{100+R} \times 100\%}$
Price ↓ R%, keep expense same	Consumption ↑ $\boxed{\frac{R}{100-R} \times 100\%}$
Population growth (n years)	$\boxed{P \times \left(1 + \frac{R}{100}\right)^n}$
Depreciation (n years)	$\boxed{P \times \left(1 - \frac{R}{100}\right)^n}$
Passing marks (two students)	Total = $\boxed{\frac{(X+Y) \times 100}{Q-P}}$

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Practice Questions (Test Yourself)

Solve these using the shortcuts above. Then practice more percentage questions online.

Q#	Question	Your Answer
1	What is 15% of 80? (Use swapping)	______
2	Find 37% of 200. (Use split method)	______
3	A's salary is 40% more than B's. B's salary is what percent less than A's?	______
4	Price increases by 20%, then 10%. Net change?	______
5	Petrol price rises 40%. By what percent must consumption drop?	______

Answers

Q#	Answer	Shortcut Used
1	12	Swapping: 80% of 15 = 12
2	74	Split: 37% = 25% + 12% = 50 + 24
3	28.57%	More/Less formula: $\frac{40}{140} \times 100$
4	32% increase	Successive change: $20 + 10 + \frac{200}{100}$
5	28.57%	Expenditure constancy: $\frac{40}{140} \times 100$

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Final Words

Master these percentages shortcut tricks for aptitude tests, and you will:

• ✅ Solve problems 3x faster
• ✅ Reduce calculation errors
• ✅ Gain confidence in the quantitative section

Your next step: Practice percentage questions daily for one week. Then watch your mock test scores rise.

Good luck! 🚀

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Frequently Asked Questions

Q: How many shortcut tricks should I memorize?
Focus on the 5 most important: Swapping, Split Method, Successive Change, More/Less Ratio, and Expenditure Constancy.

Q: Can I use these for SSC CGL and Bank exams?
Absolutely. These are standard percentage short tricks for competitive exams.

Q: Is there a PDF of these tricks?
You can save this page as PDF (Ctrl + P → Save as PDF) for offline practice.

Q: Do these work for decimal percentages like 6.5%?
Yes. Use the split method: $6.5\% = 5\% + 1.5\%$ (or $1\% + 0.5\%$).