September 7, 2026
NPAT Time and Work Questions are an important part of quantitative aptitude preparation for students appearing for the NPAT exam. These questions test how well you understand the relationship between time, work, efficiency, and the number of people involved in completing a task.
At first, Time and Work problems can look complicated because a question may involve two or more people, different efficiencies, or workers joining and leaving a task. However, the basic idea behind these questions is quite simple.
If you understand how much work a person completes in one day, you can solve most NPAT Time and Work Problems step by step.
This guide covers the important NPAT Time and Work formulas, shortcuts, solved questions, common mistakes, and practice questions. It helps students build a strong foundation in NPAT quantitative aptitude.
Time and Work questions deal with the amount of work one or more people complete within a specific period.
For example, if A can complete a job in 10 days, then A completes 1/10 of the work in one day.
Therefore, in 5 days, A will complete: 5 × 1/10 = 1/2
So, A completes half of the job in five days.
This basic concept is used repeatedly in NPAT Time and Work Questions.
Now test your understanding with these practice questions.
Question 1: A can complete a job in 16 days. What fraction of the job will A complete in 4 days?
A 1/2
B 1/4
C 3/4
D 1/8
Question 2: A can complete a job in 10 days and B can complete it in 15 days. How long will they take together?
A 5 days
B 6 days
C 7 days
D 8 days
Question 3: A and B can complete a job in 12 and 24 days respectively. What fraction of the work can they complete together in one day?
A 1/8
B 1/6
C 1/4
D 1/3
Question 4 : A is twice as efficient as B. If B takes 24 days to complete a job, how long will A take?
A 6 days
B 8 days
C 12 days
D 48 days
Question 5: 10 workers can complete a job in 18 days. Assuming equal efficiency, how many days will 15 workers take?
A 10 days
B 12 days
C 15 days
D 20 days
Question 6 :A can complete a job in 20 days and B can complete it in 30 days. What fraction of the work will they complete together in 5 days?
A 1/3
B 5/12
C 1/2
D 7/12
| Question | Correct Answer | Explanation |
|---|---|---|
| 1 | B — 1/4 | 4/16 = 1/4 |
| 2 | B — 6 days | 1/10 + 1/15 = 1/6 |
| 3 | A — 1/8 | 1/12 + 1/24 = 1/8 |
| 4 | C — 12 days | Twice the efficiency means half the time |
| 5 | B — 12 days | 10 × 18 = 15 × D |
| 6 | B — 5/12 | Combined daily work = 1/20 + 1/30 = 1/12 |
Also Read: Most important NPAT topics to Prepare Now
Here are the most common question types that are asked in exams covering the NPAT time and work topic:
| Type of Question | What You Usually Need to Find |
|---|---|
| One person working | Time or amount of work |
| Two people working together | Combined time |
| Three or more people | Combined work rate |
| Efficiency questions | Efficiency or time |
| Men and days | Number of workers or days |
| Work and wages | Individual wage share |
| Someone joins the work | Remaining time |
| Someone leaves the work | Remaining work/time |
| Partial work | Work completed or remaining |
Understanding these categories makes it easier to identify the right approach when solving NPAT Time and Work Questions.
Also attempt a free NPAT mock test to get an idea of the topics that are frequently asked in the exam.
You do not need to memorise dozens of formulas. The following concepts are enough for most basic and intermediate NPAT Time and Work Questions.
| Concept | Formula |
|---|---|
| One-day work | 1 / Number of days |
| Work completed | Daily work × Number of days |
| Time required | Total work / Daily work |
| Work | Efficiency × Time |
| Combined work | Sum of individual work rates |
| Efficiency | Work / Time |
| Men and days | Men × Days = Constant |
| Efficiency relationship | Efficiency ∝ 1 / Time |
Suppose A completes a job in 20 days.
| Particular | Calculation |
|---|---|
| Total work | 1 |
| Time | 20 days |
| Work in one day | 1/20 |
| Work in 5 days | 5/20 |
| Simplified work | 1/4 |
Therefore, A completes 1/4 of the work in 5 days.
A simple four-step approach works for many NPAT time-and-work problems.
If a person completes a job in D days:
One-day work = 1/D
If two people work together, add their individual daily work rates.
If the workers have already worked for a certain number of days, calculate how much work has been completed.
Use: Time = Remaining Work ÷ Daily Work
| Given Information | What to Do |
|---|---|
| A completes work in 10 days | A’s daily work = 1/10 |
| B completes work in 15 days | B’s daily work = 1/15 |
| A + B work together | Add 1/10 + 1/15 |
| Work already completed | Multiply daily work by days |
| Remaining work | Total work − completed work |
This approach is particularly useful when solving NPAT Time and Work Questions under time pressure. To prepare faster and more effectively, follow the NPAT study plan.
Efficiency is one of the most important concepts in Time and Work.
If a person is more efficient, they can complete the same amount of work in less time.
The relationship is: Efficiency ∝ 1/Time
This means efficiency and time are inversely proportional.
| Efficiency | Time |
|---|---|
| 1× | Original time |
| 2× | Half the original time |
| 3× | One-third of original time |
| 4× | One-fourth of original time |
| 1/2× | Double the original time |
A is twice as efficient as B. B takes 20 days to complete a job.
Therefore:
A’s time = 20 ÷ 2 = 10 days
Answer: 10 days
This is another common pattern in NPAT Time and Work Questions.
If: A’s efficiency: B’s efficiency = 2 : 3
then: A’s time : B’s time = 3 : 2
The ratio is reversed because efficiency and time are inversely proportional.
| Efficiency Ratio | Time Ratio |
|---|---|
| 1 : 2 | 2 : 1 |
| 2 : 3 | 3 : 2 |
| 3 : 4 | 4 : 3 |
| 4 : 5 | 5 : 4 |
| 5 : 7 | 7 : 5 |
A is 50% more efficient than B.
Therefore:
A’s efficiency = 150%
B’s efficiency = 100%
Efficiency ratio: 3 : 2
Time ratio: 2 : 3
If B takes 18 days:
A’s time = 18 × 2/3 = 12 days
Answer: 12 days
One of the most common NPAT Time and Work Questions involves two people working on the same task.
Suppose:
Their daily work is:
| Person | Time Taken | Work Per Day |
|---|---|---|
| A | 12 days | 1/12 |
| B | 18 days | 1/18 |
| A + B | — | 5/36 |
Therefore:
Combined work = 5/36 per day
Time required: 36/5 = 7.2 days
If A completes work in x days and B completes it in y days:
Combined time = xy/(x + y)
For 12 and 18 days:
12 × 18 / (12 + 18)
= 216/30
= 7.2 days
When two people work together, their combined time should normally be less than the time taken by either person individually.
A can complete a job in 15 days. What fraction of the work will A complete in 5 days?
| Step | Calculation |
|---|---|
| One-day work | 1/15 |
| Work in 5 days | 5 × 1/15 |
| Simplified answer | 1/3 |
A completes 1/3 of the work.
Question1: A can complete a job in 12 days, and B can complete it in 18 days. How long will they take if they work together?
Solution
| Person | One-Day Work |
|---|---|
| A | 1/12 |
| B | 1/18 |
| Combined | 1/12 + 1/18 |
| Combined work | 5/36 |
Therefore: Time = 36/5 = 7.2 days
Answer 7.2 days
Question 2 : A can complete a job in 20 days. A works alone for 5 days. What fraction of the work remains?
Solution
| Step | Result |
|---|---|
| One-day work | 1/20 |
| Work completed in 5 days | 5/20 = 1/4 |
| Total work | 1 |
| Remaining work | 1 − 1/4 |
| Final answer | 3/4 |
3/4 of the work remains.
Question 3. A can complete a job in 10 days and B can complete the same job in 15 days. How long will they take together?
Solution
A’s daily work:1/10
B’s daily work: 1/15
Combined work: 1/10 + 1/15
Taking LCM 30: 3/30 + 2/30 = 5/30 = 1/6
Therefore:
Time = 6 days
Answer 6 days
Question 4: A and B can complete a job in 10 and 15 days respectively. They work together for 3 days, after which A leaves. How many more days will B need to finish the job?
Step 1: Combined Daily Work
| Person | Daily Work |
|---|---|
| A | 1/10 |
| B | 1/15 |
| Together | 1/6 |
3 × 1/6 = 1/2
So, half the work is completed.
1 − 1/2 = 1/2
B’s daily work = 1/15
Time required:
1/2 ÷ 1/15 = 15/2
= 7.5 days
B needs 7.5 more days.
Some NPAT Time and Work Questions involve three or more workers.
A can complete a job in 12 days, B in 18 days, and C in 36 days. How long will all three take together?
| Person | Time | Daily Work |
|---|---|---|
| A | 12 days | 1/12 |
| B | 18 days | 1/18 |
| C | 36 days | 1/36 |
| Total | — | 1/6 |
Therefore:
Time = 6 days
Answer: 6 days
The LCM method can make calculations easier, especially when the question contains several fractions.
Suppose A takes 12 days and B takes 18 days.
Instead of assuming total work as 1, take:
Total work = LCM(12, 18) = 36 units
Now calculate:
| Person | Total Work | Days | Daily Work |
|---|---|---|---|
| A | 36 units | 12 | 3 units |
| B | 36 units | 18 | 2 units |
| Together | 36 units | — | 5 units |
Combined time:
36 ÷ 5 = 7.2 days
| Fraction Method | LCM Method |
|---|---|
| Uses fractions | Uses whole numbers |
| Can involve more steps | Often quicker |
| May be difficult mentally | Easier for many students |
| Good for understanding | Useful for exam calculations |
The LCM approach is especially useful when solving multiple NPAT Time and Work Questions during a timed practice session.
Men-and-days questions are based on the idea that, when all workers have equal efficiency:
Men × Days = Constant
8 workers can complete a job in 15 days. How many days will 12 workers take?
| Workers | Days |
|---|---|
| Workers | Days |
| 8 | 15 |
| 12 | D |
Therefore:
8 × 15 = 12 × D
D = 10 days
Answer: 10 days
| Number of Workers | Time Required |
|---|---|
| Number of Workers | Time Required |
| Increases | Decreases |
| Decreases | Increases |
| Doubles | Time becomes half |
| Halves | Time becomes double |
This shortcut works when the workers have equal efficiency and the other working conditions remain unchanged.
Work and wages questions are closely related to Time and Work.
The basic idea is: Wages are proportional to the work completed.
Suppose A and B have an efficiency ratio of 3:2 and work for the same amount of time.
Their work ratio will also be: 3:2
Therefore, their wage ratio will be: 3:2
| Worker | Efficiency | Work Share | Wage Share |
|---|---|---|---|
| A | 3 | 3 parts | 3 parts |
| B | 2 | 2 parts | 2 parts |
| Total | 5 | 5 parts | 5 parts |
If workers spend different amounts of time on the job, consider both efficiency and working time. Solve the above mentioned types of questions to get more familiar with the NPAT exam pattern.
Here are some useful shortcuts to remember while practising NPAT Time and Work Questions.
| Situation | Shortcut |
|---|---|
| A completes work in D days | Daily work = 1/D |
| Two people work together | Add their daily work |
| Three people work together | Add all daily work rates |
| A person leaves | Subtract their daily work |
| Efficiency doubles | Time becomes half |
| Efficiency triples | Time becomes one-third |
| Workers double | Days become half, if efficiency is equal |
| Workers halve | Days double, if efficiency is equal |
| Several fractions appear | Use LCM method |
| Same work, different efficiencies | Use inverse efficiency-time ratio |
Even when the concept is simple, students can lose marks because of calculation or interpretation errors.
| Common Mistake | What you should do |
|---|---|
| Adding the number of days | Add daily work rates |
| Forgetting inverse proportion | Higher efficiency means less time |
| Ignoring work already completed | Calculate remaining work |
| Applying Men × Days blindly | Check the efficiency assumption |
| Making unnecessary fraction calculations | Try the LCM method |
| Not checking the final answer | Compare it with the individual times |
| Spending too much time on one problem | Move on and return later when appropriate |
A good preparation strategy should move from easy questions to more complicated ones.
| Stage | Preparation Focus |
|---|---|
| 1 | Understand basic work and time |
| 2 | Practise one-person questions |
| 3 | Practise two-person questions |
| 4 | Learn efficiency and time ratios |
| 5 | Practise three-person questions |
| 6 | Solve men-and-days questions |
| 7 | Practise joining and leaving problems |
| 8 | Attempt work-and-wages questions |
| 9 | Solve mixed NPAT questions |
| 10 | Practise under a time limit |
Do not simply count how many questions you solve.
After each practice session, make a note of the questions you got wrong and identify the reason.
| Eroor Type | Example |
|---|---|
| Conceptual | Used efficiency incorrectly |
| Calculation | Arithmetic mistake |
| Interpretation | Misread the question |
| Time management | Spent too long on one question |
| Formula | Used an inappropriate shortcut |
This approach can make your NPAT quantitative aptitude preparation much more effective.
The easiest way to get comfortable with NPAT Time and Work Questions is to understand the concept instead of memorising every possible shortcut.
Keep these points in mind: Start with basic NPAT Time and Work Problems, then gradually move to efficiency, combined-work, men-and-days, and joining/leaving questions.
The more familiar you become with these patterns, the less time you will spend figuring out which method to use. Regular practice, careful error analysis, and timed revision can help you approach NPAT Time and Work Questions with much greater confidence.
For NPAT preparation, the goal should not simply be to solve more questions. The goal is to understand the method, avoid repeated mistakes, and solve familiar question patterns efficiently.
Frequently Asked Questions
Is Time and Work important for NPAT?

How can I solve NPAT Time and Work Questions faster?

What is the relationship between efficiency and time?

What is the LCM method in Time and Work?

How do I solve men-and-days questions?

SHARE