Competitive exams such as RRB NTPC, RRB Group D, RRB ALP, and RPF require candidates to solve quantitative aptitude questions accurately within a limited time. Topics such as Percentage, Profit & Loss, and Time-Speed-Distance form an important part of arithmetic preparation. Learning the right formulas and shortcuts can help reduce calculation time and improve accuracy. This article covers important short tricks, formulas, examples, and practice questions for Railway exam preparation.
Why are Short Tricks for Railway Exams Important?
The short tricks and tips are very useful for candidates appearing in the railway exams. Some of the reasons to learn short tricks are as follows:
- The time limit is strict; you cannot spend more than 40–50 seconds on one question.
- Many questions are calculation-based; tricks help reduce lengthy steps.
- Shortcuts improve accuracy, as you rely on tested formulas.
- With practice, they help build confidence and speed during the exam.
Short Tricks for Percentage Problems
Percentage is the base of several arithmetic topics, including Profit & Loss, Discount, Simple Interest, Ratio, and Data Interpretation.
| Concept | Formula / Trick | Example |
| Basic Percentage Conversion | x% = x/100 | 25% = 1/4, 50% = 1/2, 75% = 3/4, 12.5% = 1/8, 20% = 1/5 |
| Percentage Change (Increase & Decrease) | Net change = (x²/100)% decrease | 20% ↑ then 20% ↓ → Net = 4% decrease |
| Finding Percentage Quickly | (x/y) × 100 | 45 is what % of 90 → 50% |
| Successive Percentage Increase | (a + b + ab/100)% | 10% + 20% → Net = 32% |
Short Tricks for Profit & Loss Problems
Profit and Loss questions are closely related to percentages. Candidates should first understand the relationship between Cost Price, Selling Price, Marked Price, Profit, Loss, and Discount.
| Concept | Formula |
|---|---|
| Profit | SP – CP |
| Loss | CP – SP |
| Profit % | (Profit/CP) × 100 |
| Loss % | (Loss/CP) × 100 |
| SP at p% Profit | CP × (100+p)/100 |
| SP at l% Loss | CP × (100-l)/100 |
Where:
CP = Cost Price
SP = Selling Price
Ratio Shortcut
If profit is 20%:
CP : SP
= 100 : 120
= 5 : 6
If loss is 20%:
CP : SP
= 100 : 80
= 5 : 4
This ratio method can help solve many Profit and Loss questions quickly.
Short Tricks for Time, Speed, and Distance Problems
Railway exams always have a good number of time-speed questions, often framed around trains, platforms, and boats. The important details for time, speed and distance problems are as follows:
1. Basic Formula
- Speed = Distance / Time
- Time = Distance / Speed
- Distance = Speed × Time
2. Relative Speed
- When objects move in the same direction: Relative Speed = (A – B)
- When objects move in opposite directions: Relative Speed = (A + B)
Example: Two trains moving at 60 km/h and 40 km/h in opposite directions. Relative speed = 100 km/h.
3. Shortcut for Crossing Problems
- If two trains of lengths L1 and L2 cross each other in t seconds,
Relative Speed = (L1 + L2)/t - If a train of length L crosses a platform of length P in t seconds,
Speed = (L + P)/t
4. Average Speed Trick
When equal distance is covered at two speeds:
- Average Speed = (2xy)/(x + y)
Example: A man travels to a place at 30 km/h and returns at 60 km/h. Average speed = (2×30×60)/(30+60) = 40 km/h.
5. Boat & Stream Trick
- Downstream Speed = (Boat + Stream)
- Upstream Speed = (Boat – Stream)
- Speed of Boat = (Downstream + Upstream)/2
- Speed of Stream = (Downstream – Upstream)/2
Tips to Apply Short Tricks Effectively
As an exam applicant, you must know how to apply these short tricks and tips effectively to score well in the examination. Some of the ways are given below:
- Practice Daily: Tricks work only when you are comfortable applying them quickly.
- Use Approximation: In MCQs, sometimes options are far apart—approximation can save time.
- Avoid Over-Reliance: Use tricks when calculations are lengthy; otherwise, basic formulas are enough.
- Solve Previous Year Papers: Many railway exam questions follow a set pattern.
- Make a Formula Sheet: Keep a one-page summary of all percentage, profit-loss, and speed-distance tricks for revision.
Example Questions with Short Trick Solution
We have given below some sample questions with their solutions. Candidates can follow these questions to have an idea about the difficulty level:
Q1. A man buys an article for ₹500 and sells it at a profit of 20%. What is the selling price?
SP = (100 + 20)/100 × 500 = (120/100) × 500 = ₹600.
Q2. A train 150 m long crosses a pole in 15 seconds. Find its speed in km/h.
Speed = Distance/Time = 150/15 = 10 m/s = 10 × 18/5 = 36 km/h.
Q3. Price of a product increases by 20% and then decreases by 20%. Find net change.
Net change = (20²/100)% = 4% decrease.
Practice MCQs for Railways Using Short Tricks
Practice MCQs for Railway exams using short tricks to improve speed and accuracy. Focus on topics like percentage, ratio, number series, and simplification, and apply quick methods like approximation and elimination to solve questions faster and score better.
Q1. Ramesh invested ₹45,000 at 8% per annum simple interest and ₹30,000 at 12% per annum compound interest (compounded annually). What is the total interest earned after 3 years? (Round to nearest ₹)
Q2. A sum of money doubles itself at compound interest in 4 years. In how many years will it become 8 times?
Q3. The difference between compound interest and simple interest on a sum for 3 years at 10% per annum is ₹620. Find the principal.
Q4. Seema took a loan of ₹1,20,000 at 15% per annum compound interest, compounded half-yearly. What amount will she pay after 1.5 years?
Q5. Two equal sums are lent at 6% simple interest and 6% compound interest respectively for 2 years. If the difference in interest is ₹108, find the sum lent in each case.
Q6. A man invests a certain sum at 10% per annum simple interest and gets ₹4,500 as interest after 3 years. If he had invested the same sum at 10% per annum compound interest (annually), how much more interest would he have earned?
Q7. At what rate of compound interest per annum will ₹64,000 amount to ₹68,921 in 3 years?
Q8. A sum amounts to ₹2,916 in 2 years and ₹3,149.28 in 3 years at compound interest. Find the principal.
Q9. Vikram borrowed ₹80,000 at 9% per annum simple interest. After 2 years, he repaid ₹50,000. How much must he pay at the end of 5 years from the start to clear the debt?
Q10. The simple interest on a sum for 5 years at 12% per annum equals the compound interest on ₹18,000 for 2 years at 10% per annum. Find the principal for simple interest.
Q11. A trader marks his goods 40% above cost price and offers a discount of 15%. He uses a false weight of 800 g instead of 1000 g. Find his actual profit percentage.
Q12. A sells to B at 20% profit, B sells to C at 15% profit, and C sells to D at 10% loss. If D pays ₹18,414, what did A pay (cost price for A)?
Q13. A shopkeeper sells 12 articles at the cost price of 15 articles. Find his profit percentage.
Q14. By selling 33 metres of cloth, a shopkeeper gains a profit equal to the selling price of 11 metres. Find the profit percentage.
Q15. A man bought two watches. He sold one at 20% profit and the other at 20% loss. If the selling price of each watch was ₹960, find the net loss or profit in rupees.
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Important Fraction to Percentage Conversions for Railway Exams
Fraction-to-percentage conversions are extremely useful in Percentage, Profit & Loss, Data Interpretation, Ratio, Average, and other arithmetic questions. Memorising the common values given below can help candidates reduce calculation time during Railway exams.
| Fraction | Percentage |
| 1/2 | 50% |
| 1/3 | 33.33% |
| 1/4 | 25% |
| 1/5 | 20% |
| 1/6 | 16.67% |
| 1/8 | 12.5% |
| 1/9 | 11.11% |
| 1/10 | 10% |
| 1/12 | 8.33% |
| 1/16 | 6.25% |
| 2/3 | 66.67% |
| 3/4 | 75% |
| 3/5 | 60% |
| 5/8 | 62.5% |
| 7/8 | 87.5% |
Quick Percentage Tricks
- 50% of a number = Divide by 2
- 25% of a number = Divide by 4
- 20% of a number = Divide by 5
- 12.5% of a number = Divide by 8
- 10% of a number = Divide by 10
- 5% of a number = Find 10% and divide by 2
Example:
12.5% of 640 = 640 ÷ 8 = 80
Successive Percentage Change
If a quantity changes by a% and then by b%:
Net Change = a + b + ab/100
Treat an increase as positive and a decrease as negative.
Example:
20% increase followed by 10% decrease:
20 – 10 – (20 × 10)/100
= 10 – 2
= 8% increase
If the same percentage x% is first increased and then decreased:
Net Decrease = x²/100
For example:
20% increase followed by 20% decrease
= 20²/100
= 4% decrease
Reverse Percentage
If the final value after an x% increase is known:
Original Value = Final Value × 100/(100 + x)
If the final value after an x% decrease is known:
Original Value = Final Value × 100/(100 – x)
Profit, Loss and Discount Short Tricks
Profit & Loss questions become easier when candidates understand the relationship between Cost Price, Selling Price, Marked Price, and Discount.
Important Formulas
| Concept | Formula |
|---|---|
| Profit | SP – CP |
| Loss | CP – SP |
| Profit % | Profit/CP × 100 |
| Loss % | Loss/CP × 100 |
| SP at p% Profit | CP × (100 + p)/100 |
| SP at l% Loss | CP × (100 – l)/100 |
| Discount | MP – SP |
| Discount % | Discount/MP × 100 |
Where:
CP = Cost Price
SP = Selling Price
MP = Marked Price
Ratio Shortcut
If an article is sold at 20% profit:
CP : SP = 100 : 120 = 5 : 6
If an article is sold at 20% loss:
CP : SP = 100 : 80 = 5 : 4
Successive Discount Trick
For two successive discounts of a% and b%:
Equivalent Discount = a + b – ab/100
Example:
Discounts of 20% and 10%
= 20 + 10 – (20 × 10)/100
= 28%
False Weight Shortcut
If a shopkeeper charges for 1000 g but gives only x grams:
Profit % = [(1000 – x)/x] × 100
Example:
If only 800 g is given instead of 1000 g:
Profit %
= (200/800) × 100
= 25%
Time, Speed and Distance Short Tricks
Time, Speed and Distance questions in Railway exams often involve trains, platforms, relative speed, and average speed.
Basic Formulas
Speed = Distance / Time
Time = Distance / Speed
Distance = Speed × Time
Speed Conversion
| Conversion | Shortcut |
|---|---|
| km/h to m/s | × 5/18 |
| m/s to km/h | × 18/5 |
Useful direct conversions:
| km/h | m/s |
|---|---|
| 18 | 5 |
| 36 | 10 |
| 54 | 15 |
| 72 | 20 |
| 90 | 25 |
Relative Speed
Same direction:
Relative Speed = Difference of speeds
Opposite direction:
Relative Speed = Sum of speeds
Train Questions
Train crossing a pole/person:
Distance = Length of Train
Train crossing a platform:
Distance = Train Length + Platform Length
Two trains crossing each other:
Distance = Sum of lengths of both trains
Time can then be calculated using:
Time = Distance / Relative Speed
Average Speed
For equal distances covered at speeds x and y:
Average Speed = 2xy/(x + y)
For equal time spent at speeds x and y:
Average Speed = (x + y)/2
Example:
A person travels equal distances at 40 km/h and 60 km/h.
Average Speed
= (2 × 40 × 60)/(40 + 60)
= 48 km/h
Simple and Compound Interest Short Tricks
Simple Interest and Compound Interest questions are also common in Railway arithmetic sections and are useful to revise along with Percentage and Profit & Loss.
Simple Interest
SI = PRT/100
Where:
P = Principal
R = Rate
T = Time
Amount = Principal + SI
Compound Interest
For annual compounding:
Amount = P(1 + R/100)ᵀ
CI = Amount – Principal
For half-yearly compounding:
- Rate becomes R/2
- Number of periods becomes 2T
Difference Between CI and SI for 2 Years
Difference = P × (R/100)²
Example:
Principal = ₹10,000
Rate = 10%
Difference
= 10,000 × (10/100)²
= ₹100
Quick Calculation Tricks for Railway Exams
Fast calculation can significantly improve performance in arithmetic questions.
| Calculation | Shortcut |
|---|---|
| Multiply by 5 | Multiply by 10 and divide by 2 |
| Multiply by 25 | Multiply by 100 and divide by 4 |
| Multiply by 125 | Multiply by 1000 and divide by 8 |
| Find 5% | Find 10% and divide by 2 |
| Find 15% | Add 10% and 5% |
Examples:
48 × 25
= 4800 ÷ 4
= 1200
32 × 125
= 32,000 ÷ 8
= 4,000
Common Mistakes to Avoid
Candidates should avoid the following errors while applying short tricks:
- Profit % and Loss % are generally calculated on Cost Price.
- Discount is calculated on Marked Price.
- Do not directly add successive percentage changes.
- Do not use the simple average of two speeds when equal distances are covered.
- Convert km/h into m/s when distance is given in metres and time in seconds.
- In two-train crossing questions, include the lengths of both trains.
- Always identify the concept before applying a shortcut.
Railway Maths Short Tricks at a Glance
| Topic | Formula / Trick |
|---|---|
| x% of y | x × y / 100 |
| Equal % increase and decrease | x²/100% decrease |
| Successive increase | a + b + ab/100 |
| Successive discount | a + b – ab/100 |
| Profit % | Profit/CP × 100 |
| Loss % | Loss/CP × 100 |
| km/h to m/s | × 5/18 |
| m/s to km/h | × 18/5 |
| Equal-distance average speed | 2xy/(x + y) |
| Opposite-direction relative speed | Sum of speeds |
| Same-direction relative speed | Difference of speeds |
| Simple Interest | PRT/100 |
How to Use Short Tricks Effectively
Short tricks are most useful when combined with regular practice. Candidates should:
- Memorise common fractions and percentages.
- Practise squares, cubes, and basic calculations.
- Solve previous-year Railway exam questions.
- Use approximation only when options are sufficiently far apart.
- Practise questions with a timer.
- Review calculation and conceptual mistakes after every mock test.
The aim should be to improve both speed and accuracy rather than applying shortcuts blindly.
FAQs
With the knowledge of right short tricks and formulas, you can save time and solve more questions quickly.
As an applicant, it is recommended not to spend more than 40–50 seconds on one question.
Yes, it is recommended to attempt mock tests regularly to improve your performance.
By learning formulas like net percentage change, net profit with discount, relative speed, and average speed, you can attempt more questions accurately within the time limit.
You must learn these short tricks and tips for competitive exams like RRB NTPC, Group D, ALP, and RPF.
Hello! This is Arijit Dutta. I am a skilled Content Writer at Oliveboard with nearly 3+ years of experience in crafting engaging, informative, and exam-focused content for the Railways Domain. With a strong command of language and a keen understanding of learner needs, I contribute significantly to Oliveboard’s mission of delivering high-quality educational resources. Passionate about clear communication and continuous learning, I consistently create content that helps government job aspirants achieve their goals. Outside of work, I enjoy playing cricket and listening to music, which helps me stay balanced and creative in my professional journey.
