Hello Students,
I am Rahul C Sir, an IIT-level Mathematics expert and aptitude trainer with years of experience helping students crack competitive examinations such as IBPS PO, IBPS Clerk, SBI PO, SBI Clerk, SSC CGL, Railway, and various government recruitment exams. Among the most important quantitative aptitude topics in banking examinations is Time and Work.
Many students find Time and Work questions confusing because they involve multiple workers, efficiency calculations, pipes and cisterns, work-sharing concepts, and varying work rates. However, the reality is that most questions are based on a few simple formulas and logical shortcuts. Once you understand efficiency, unitary method, and work equivalence, you can solve even difficult questions within a minute.
In IBPS PO and Clerk exams, Time and Work questions frequently appear in prelims and mains examinations. These questions are scoring because they follow predictable patterns. Instead of lengthy calculations, smart candidates use shortcuts and efficiency-based methods to reach answers quickly.
In this guide, I will share practical tips, tricks, formulas, and solved examples that can significantly improve your speed and accuracy. Whether you are a beginner or an advanced aspirant, these concepts will help you tackle Time and Work questions confidently and maximize your score in the Quantitative Aptitude section.
1. Understanding the Basic Concept of Time and Work
The fundamental principle behind Time and Work is straightforward: Work Done = Efficiency × Time.
If a person completes a job in 10 days, then their one-day work is:
1/10
Similarly, if another person completes the same work in 20 days, their one-day work is:
1/20
The total work is generally assumed to be 1 unit. The more work a person completes in one day, the higher their efficiency.
Example
A can complete a task in 12 days.
One day’s work of A = 1/12
Work completed in 4 days = 4/12 = 1/3
Therefore, after 4 days, one-third of the work is completed.
Tip
Always convert the given days into one-day work before attempting the question.
Shortcut
Remember:
- If work increases, time decreases.
- If efficiency increases, time decreases.
- Efficiency and time are inversely proportional.
Understanding this basic relationship forms the foundation for solving advanced Time and Work questions in banking examinations.
2. Mastering the Efficiency Method
Efficiency-based solving is one of the fastest approaches used by toppers.
Suppose:
- A completes work in 10 days.
- B completes work in 20 days.
Efficiency ratio:
A : B = 20 : 10 = 2 : 1
This means A is twice as efficient as B.
Example
A can complete a task in 15 days and B in 30 days.
Efficiency ratio:
30 : 15 = 2 : 1
Therefore, A does twice the work of B in the same time.
Trick
Instead of calculating fractions repeatedly, directly compare efficiencies.
If:
- A = 10 days
- B = 20 days
- C = 40 days
Efficiency ratio becomes:
4 : 2 : 1
This shortcut saves valuable exam time.
Exam Benefit
Many IBPS questions involving combined work, wages, and work distribution can be solved solely using efficiency ratios without using fractions.
The efficiency approach is among the most powerful techniques for competitive exams and should be practiced regularly.
3. Using LCM Method to Simplify Questions
The LCM method is a favorite among banking aspirants because it eliminates fractions.
Example
A completes work in 12 days.
B completes work in 18 days.
Take LCM of 12 and 18.
LCM = 36
Assume Total Work = 36 units.
Then:
A’s efficiency = 36/12 = 3 units/day
B’s efficiency = 36/18 = 2 units/day
Combined efficiency:
3 + 2 = 5 units/day
Time taken together:
36/5 = 7.2 days
Why This Method Works
Instead of dealing with fractions like:
1/12 + 1/18
You work with whole numbers.
Shortcut
Whenever multiple workers are involved:
- Find LCM of working days.
- Assume total work = LCM.
- Calculate daily efficiencies.
- Add efficiencies.
- Divide total work by total efficiency.
This approach significantly reduces calculation errors and is highly useful during prelims.
4. Solving Combined Work Questions Quickly
Combined work questions are extremely common in IBPS examinations.
Formula
Combined Work = Sum of Individual Efficiencies
Example
A can complete work in 15 days.
B can complete work in 10 days.
One day work:
A = 1/15
B = 1/10
Together:
1/15 + 1/10
= 2/30 + 3/30
= 5/30
= 1/6
Therefore, together they finish the work in 6 days.
Shortcut Using LCM
Take LCM = 30
A efficiency = 2
B efficiency = 3
Combined = 5
Time = 30/5
= 6 days
Exam Tip
Whenever two or more workers work together, think in terms of efficiency rather than fractions. This method drastically improves speed.
Practice at least 20 combined work questions to become comfortable with this approach.
5. Worker Leaves the Job Midway Questions
These are frequently asked in mains examinations.
Example
A can complete work in 12 days.
B can complete work in 18 days.
They work together for 4 days.
How much work remains?
Using LCM = 36
A efficiency = 3
B efficiency = 2
Combined efficiency = 5
Work done in 4 days:
5 × 4 = 20 units
Remaining work:
36 − 20 = 16 units
Tip
Always calculate:
- Total work.
- Work completed.
- Remaining work.
Then solve the second phase separately.
Shortcut
Break the question into stages.
Stage 1 = Joint work
Stage 2 = Remaining work
This structured approach avoids confusion and helps solve complex questions efficiently.
6. Time and Work Based on Men, Women, and Children
Banking exams often introduce workers of different efficiencies.
Example
2 men = 3 women
3 women = 6 children
Find ratio.
Men : Women : Children
= 6 : 4 : 2
= 3 : 2 : 1
Application
Suppose:
1 man completes work in 15 days.
Then:
1 woman takes:
15 × 3/2
= 22.5 days
Trick
Convert all workers into a single unit.
Either convert everything into:
- Men
- Women
- Children
This simplifies calculations considerably.
Exam Benefit
Questions involving labor groups become much easier when converted into equivalent units.
7. Mastering Alternate Day Work Questions
These questions appear regularly in IBPS and SBI exams.
Example
A completes work in 12 days.
B completes work in 18 days.
They work on alternate days starting with A.
Using LCM = 36
A efficiency = 3
B efficiency = 2
Two-day work:
3 + 2 = 5
After 6 cycles:
6 × 5 = 30 units
Remaining:
36 − 30 = 6 units
Day 13:
A works and completes 3 units.
Remaining = 3
Day 14:
B completes remaining 3 units.
Answer = 14 days.
Trick
Calculate work done in one complete cycle.
Then find remaining work.
This approach is much faster than day-by-day calculations.
8. Pipes and Cisterns as Time and Work Questions
Pipes and cisterns are simply Time and Work in disguise.
Example
Pipe A fills tank in 12 hours.
Pipe B fills tank in 18 hours.
Together?
LCM = 36
A efficiency = 3
B efficiency = 2
Combined = 5
Time = 36/5
= 7.2 hours
If a Pipe Empties
Pipe C empties tank in 36 hours.
Efficiency = −1
Net efficiency:
3 + 2 − 1
= 4
Time:
36/4
= 9 hours
Exam Trick
Treat filling pipes as positive efficiency and emptying pipes as negative efficiency.
Most pipe questions become easy Time and Work problems after this conversion.
9. Work and Wages Questions
Wages are distributed according to work done.
Example
A and B complete a task together.
Efficiency ratio:
A : B = 3 : 2
Total payment = ₹5000
A’s share:
(3/5) × 5000
= ₹3000
B’s share:
(2/5) × 5000
= ₹2000
Shortcut
Payment Ratio = Efficiency Ratio
Important Rule
Higher efficiency = More work = Higher wages
Many banking questions combine Time and Work with ratio and proportion concepts.
Understanding this relationship can help solve questions in less than 30 seconds.
10. High-Speed Exam Tricks for IBPS PO and Clerk
Here are the most important shortcuts used by successful candidates:
Trick 1
Use LCM method whenever possible.
Trick 2
Memorize common efficiency conversions:
- 10 days → 1/10
- 20 days → 1/20
- 30 days → 1/30
Trick 3
Use efficiency ratios instead of fractions.
Trick 4
Break complex questions into phases.
Trick 5
Convert men, women, children into equivalent units.
Trick 6
Treat pipes as workers.
Trick 7
Remember:
Efficiency ∝ 1/Time
Trick 8
Focus on approximation when answer options are far apart.
Trick 9
Practice previous year IBPS questions.
Trick 10
Avoid lengthy fraction calculations by assuming total work as LCM.
Consistent practice of these shortcuts can dramatically improve speed and accuracy during the examination.
How Teachers from Odtutor Can Help
At Odtutor, experienced aptitude trainers provide personalized guidance for IBPS PO, IBPS Clerk, SBI, SSC, Railway, and other competitive examinations. Our teachers focus on concept clarity, shortcut techniques, exam-oriented practice, previous-year question analysis, and speed-building strategies. Students receive one-on-one doubt support, structured study plans, mock test guidance, and topic-wise practice sessions. Whether you struggle with Time and Work, Simplification, Data Interpretation, Number Series, or Arithmetic, Odtutor tutors can help you build confidence and improve your performance through customized learning approaches designed specifically for competitive exam success.