Time and Work is a frequently asked and high-scoring topic in the Quantitative Aptitude section of competitive exams like SSC, Banking, and Railways. Whether it’s calculating how long two individuals can complete a task together or figuring out how efficiently a job is done, this topic checks your understanding of ratios, proportions, and logical sequencing.
In this blog, we will provide all the details about the Time and Work questions from basic concepts and formulas to short tricks, solved questions from 2024–25 exams, and more.
What Is Time and Work in Quantitative Aptitude?
Time and Work is a fundamental topic in Quantitative Aptitude that deals with measuring the efficiency of individuals or machines performing tasks over time. It builds upon concepts from ratio and proportion, unitary method, and LCM.
This topic is common in almost all competitive exams because it tests logical reasoning, speed, and the ability to manage complex calculations under time pressure.
Skills Required:
- Basic arithmetic (LCM, ratios, percentages)
- Logical sequencing
- Efficiency-based calculations
- Time-speed optimization
Why Is Time and Work Important in Competitive Exams?
Understanding Time and Work helps candidates solve a wide range of real-life and exam-oriented problems involving jobs completed by people, machines, or groups in a given time.
| Exam | No. of Questions | Difficulty |
| SSC CGL / CHSL | 1–2 | Easy |
| IBPS PO / SBI PO | 1–2 | Moderate |
| RRB NTPC / Group D | 1 | Easy |
| State PSC / Police | 1–2 | Moderate |
Time and Work Quantitative Aptitude Short Notes
Some of the important notes aspirants must keep in mind while solving questions based on Time and Work are as follows:
| Term | Details |
| Work | The total task to be done (generally considered as 1 unit unless specified). |
| Efficiency | Amount of work done per unit of time. |
| Time | The duration taken to complete the work. |
| LCM Approach | Used to assume total work for simplifying calculations. |
| Work and Wages | Wages are distributed in the ratio of work done. |
| Alternate Work | Situations where different persons work on alternate days. |
Concepts Used in Time and Work Questions
The concepts used in Time and Work questions are as follows:
| Concept | Explanation |
| Basic Formula | Work = Rate × Time |
| Efficiency Comparison | More efficiency → Less time |
| Total Work | Often assumed as LCM of individual times |
| Combined Work | 1/A + 1/B for A and B working together |
| Negative Work | Used when a pipe/person does the opposite of the task (like leakage/draining) |
| One Day’s Work | 1/Total time to complete the job |
What Are the Types of Time and Work Questions in Quantitative Aptitude?
Types of Time and Work questions commonly asked are as follows:
- Direct Time-Efficiency Problems: Basic questions using formula Work = Time × Efficiency
- Combined Work: Two or more persons working together or alternately
- Work and Wages: Wages divided in proportion to work done
- Pipes and Cisterns: Same logic applied to tanks filled/drained
- Inverse Problems: Work undone or uncompleted scenarios
Time and Work Formulas for Quantitative Aptitude
Use these formulas for rapid solving:
- Work = Time × Efficiency
- Efficiency = 1 / Time
- If A can do a work in ‘x’ days, B in ‘y’ days
→ Together = xyx+y\frac{xy}{x + y}x+yxy days - If total work = W, and A does ‘a’ work/day
→ Time = W / a - Wage Ratio = Work Ratio
- Alternate Day Work: Use LCM of days worked and alternate pattern tracking
Time and Work Tricks for SSC CGL and Other Exams
Some of the effective time and work question tricks are as follows:
- Assume total work as LCM of given days to simplify complex fractions
- Convert time into fractions (like 1/2 day = 0.5, etc.) for faster calculation
- Use unit work approach for one-day or one-hour work logic
- Avoid decimal calculations — work with ratios and LCM
- For pipes and cisterns, treat filling as +ve work, draining as –ve work
- Reverse engineer the question using options for time-bound mocks
- Break alternate day cycles into full and half cycles
Solved Time and Work Questions from 2024–25 Exams
Solved questions based on previous exams are as follows:
SSC CGL 2024 Tier 1 – Shift 2 (Memory-Based)
Q: A can do a piece of work in 10 days, B in 15 days. They work together for 3 days. How much work is left?
Ans: 710\frac{7}{10}107 work left
Explanation: A’s 1-day work = 1/10, B’s = 1/15
Together = 1/6
Work done in 3 days = 3 × 1/6 = 1/2
Remaining = 1 – 1/2 = 1/2
IBPS PO Prelims 2024
Q: A and B together can do a work in 12 days. A alone can do it in 20 days. In how many days can B alone do it?
Ans: 30 days
Explanation:
A + B = 1/12
A = 1/20
B = 1/12 – 1/20 = 1/30
Based on RRB Group D Mock
Q: A does 60% of work in 12 days. How many more days to complete full work?
Ans: 8 days
Explanation:
60% = 12 days ⇒ 100% = (12/60) × 100 = 20 days
Remaining = 20 – 12 = 8 days
Time and Work Concepts for Bank Exams
Bank exams often frame logic-based or symbolic questions around Time and Work. These may involve indirect relations or require candidates to use mental calculation speed.
Example:
A can finish work in 16 days, B is 33.33% more efficient than A.
How many days will B take?
Ans: 12 days
Explanation: If A’s efficiency = 3 units/day, B = 4 units/day → Time = 48/4 = 12
Common Mistakes to Avoid while Solving Time and Work
While solving Time and Work problems in competitive exams, candidates often make avoidable mistakes that lead to incorrect answers.
- Ignoring unit conversions (e.g., hours to days) – Always align units before starting calculations.
- Not using the LCM method – Direct fractions can be slow; assuming total work as LCM simplifies the process.
- Assuming wrong total work – Always choose a multiple or LCM of given time durations to avoid errors.
- Confusing efficiency with speed – Efficiency refers to work/time, not to distance/time like speed.
- Misinterpreting draining/filling logic – Treat filling as positive work and draining as negative work, especially in pipe and cistern problems.
FAQs
Time = Work ÷ Efficiency.
Assume total work as the LCM of individual time durations.
Add their one-day work: 1/A + 1/B.
Use ratio-based comparison to divide work accordingly.
Find one-day work first, then multiply or divide to find total time or work.
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