Time to work upon concepts of ‘Time and Work’

types of question on time and work in Mathematics

Folks! Are you having a tough time assimilating all the concepts of ‘time and work in Mathematics’? We all have been there and hands down, time and work is one of the complicated topics holding a lot of importance in any examination be it Bank, SSC, Law, MBA, Civils or your school level exams. Read, kinds of Compound and Simple Interest questions in exams. The sooner you get a hang of it, the better. It is for all of us to know that this difficult-looking concept is not as difficult as it seems. Just a few tips and tricks, proper comprehension of questions and a correct approach towards solving the questions is all it takes to ace questions on time and work in Mathematics in your exams.

Time is dimension acting upon everything in this universe. Everything revolves around the constraints of time. Efficiency in production depends on the time taken. Questions on time & work concept talk of individuals’ efficiency. Also, depending on the kind of work and the efficiency of the labour in use, we can calculate the number of days required for the work to be completed and the amount of labor to be put in use. Hence, this concept of efficiency can be applied to varied fields. Efficiency questions in SSC or in other recruitment tests are common.

Kinds of Questions on time and work in Mathematics

Number of days taken by a person to complete a work gives the efficiency of that person. This can be expressed as (1/n), where n is the number of days taken to complete work, or in terms of a percentage.

Example: In case of the work being done in a village, under the model-village programme, efficiency of labour can be considered as the factor that defines on the number of people required to complete a piece of work. If workers from a number of sources are considered, then depending on the efficiency and the number of days to complete the work, the contract can be given. This hinges on the funds having been allocated to the village by the Member of Parliament.

  • Negative Work:

This is like the case of a number of pipes filling a water-tank; a number of pipes fill the tank at different speeds while one of the pipes does the negative work, with liquid being drained out using this pipe. This kind of question can be a part of a test paper in other forms as well.


  • A concept used in riddles and entrance test questions. Filling a water tank is a common example of this kind of question.
  • In case of work being done to complete a report on a Government scheme and parts of the report being rejected on a daily basis, how long would it take on an average to complete the report. Also, would another person be required to work on the report and complete it on time?
  • Inverse Proportion (Product Constancy)

This deals with formulae with multiple variables. When value of a variable is increased, change in any other variable can be measured using the percentages concept.

Example: In case of pollution, given that a certain number of variables cause pollution, if one of the factors increases or decreases, then what would be the percentage increase in particulate matter, ozone molecules above or at the 16 km radius from the surface of the earth, Carbon-dioxide, etc.

  • Relation between efficiencies

Efficiency is defined as 1/n. Efficiency of a number of people involved can be added to find out the amount of work completed. Rest of the work can be completed by workers with efficiency such that the work can be completed in the number of days as required. If the number of days is to be reduced, then the efficiency has to be increased.

Example: Efficiency of A, B and C on a piece of work is 10%, 8.33% and 6.66% respectively. Total work completed is thus 25% of the total. How many workers, with what efficiency can complete the work in next 4 days? Question can be either on efficiency or the number of workers. In case of data interpretation or in order to bring in more complexity, one can go into further details or add more.

Strategy for solving time and work in Mathematics:

  • It is common for examiners to set the paper in such a manner that at least 2 efficiency questions in SSC paper are there in each of the sets. Fractions and percentages can both be used. Percentages make solving easier.
  • Number of questions from this concept can range from 2-3. These do not require time using the percentages concept. A number of techniques required to solve such questions are stated in SSC or pre-MBA entrance test books. Thus, that solving methodology can be used.

So students devote time to ‘time and work in Mathematics’ and work upon it. Do not forget to take practice tests based on this topic and analyze your performance to master this area.
You might also like to read our post on Logical Reasoning questions-level of difficulty and challenging questions of Data Interpretation.

Good luck!