Questions
3 questions per paper
Difficulty
Medium
Importance
High yield for SSC and banking quant sections
Overview
Time, Work, and Wages is a fundamental quantitative aptitude topic that tests your ability to relate worker efficiency, task completion time, and proportional remuneration. Mastering this topic is essential for clearing the cut-offs in SSC and banking exams as it relies on the relationship where total work equals efficiency multiplied by time.
Time and Work Essentials
The core of this topic lies in the inverse relationship between time and efficiency when the total work remains constant. Use the Least Common Multiple (LCM) method to assign a fixed value to the total work, which simplifies calculations significantly compared to the traditional fractional method.
- Work = Efficiency × Time
- If A takes 'a' days and B takes 'b' days, their combined work time is (ab)/(a+b)
- Efficiency is inversely proportional to time for the same amount of work
- Total work is assumed to be the LCM of individual times taken
- Efficiency of A + B = Total Work / (Time taken by A+B)
Work Equivalence (Chain Rule)
This subtopic deals with complex scenarios involving multiple groups working simultaneously under different conditions. The chain rule helps calculate the effect of changing the number of men, hours, or days on the total output.
- M1 × D1 × H1 / W1 = M2 × D2 × H2 / W2
- M refers to men, D to days, H to hours, and W to the work done
- Always keep the work (W) in the denominator
- If work is the same, use M1 × D1 = M2 × D2
- Include efficiency factors if specified as 'M1 × D1 × E1 = M2 × D2 × E2'
Pipes and Cisterns
Pipes and Cisterns is an extension of Time and Work where incoming flows are treated as positive work and outgoing (leakage) flows as negative work. The mechanics remain identical to working with multiple people, but you must strictly track the sign convention.
- Inlet pipe = positive efficiency
- Outlet pipe/leakage = negative efficiency
- Net efficiency = (Inlet efficiency - Outlet efficiency)
- If a tank is half full, adjust the total work requirement accordingly
- Time to fill = Total Capacity / Net efficiency
Wages and Efficiency
In competitive exams, wages are distributed strictly in proportion to the amount of work done, which is directly proportional to the efficiency of the individual over the same time period. When time differs, wages are distributed based on the product of efficiency and time spent.
- Wages are distributed in the ratio of work done
- If time is constant, share of wage is proportional to efficiency ratio
- If efficiency is constant, share of wage is proportional to time ratio
- Ratio of wages = (E1 × T1) : (E2 × T2) : (E3 × T3)
- Always calculate the final ratio before dividing the total amount
Formula Sheet
Total Work = Efficiency × Time
M1 × D1 × H1 / W1 = M2 × D2 × H2 / W2
Combined Time = (a × b) / (a + b)
Wages Ratio = (E1 × T1) : (E2 × T2)
Exam Tip
Always use the LCM method to fix total work; avoid fractions at all costs to minimize calculation errors and save time during the exam.
Common Mistakes
- Treating leakage efficiency as positive in Pipes and Cisterns problems, leading to an incorrect total calculation.
- Assuming wages are split equally without accounting for individual differences in efficiency or time spent on the job.
- Failing to convert units (e.g., minutes to hours) when calculating work done by pipes operating at different rates.
More Revision Notes
Ready to test yourself?
Play topic-wise Time, Work & Wages questions in Aspirant Arcade — gamified MCQ practice.
Download Free