Time and Work Questions for CAT: Concepts and Tips to Solve CAT Time and Work Questions

By Aditi Joshi|Updated : April 13th, 2022

Time and Work Questions for CAT are an important part of Arithmetic questions of quantitative ability questions. It is an essential topic, and the aspirants can expect 2-3 questions compulsorily from this chapter. CAT Time and Work Questions are tricky and one needs to prepare well to ace these questions accurately. The concepts for Time and Work remain the same; however, the types of questions may vary. 

As per the analysis of previous years’ CAT exams Time and Work Questions for CAT hold weightage, as it includes various other mathematical applications like pipe and cisterns.The difficulty level may vary from year to year, so it is recommended to practise these questions with a proper and constructed approach. Here, our experts have made a detailed analysis of Time and Work concepts that are used in the questions that appear in CAT exams to help the aspirants to prepare for the topic well.

Table of Content

Time and Work Concepts for CAT

The aspirants must be well aware of the concepts and the types of questions for Time and Work, which they may face at the time of the CAT Exam. Time and Work CAT questions deal with questions like; time taken by an individual or a group of individuals to complete a piece of work and the efficiency of the work done by each of them. So, the basic types of questions that may be asked in the exam are as follows:

  • Find the efficiency of the individual or the group.
  • Find the time taken to complete the work by the individual or the group.
  • Find the amount of work completed within a certain period by the individual or the group

Time and Work Concepts for CAT - Negative Work

As per the concepts used in CAT Time and Work question, negative work increases work time. For example, there are two people, X and Y, who are working on making a table. Assume, that there is another person, Z, who is assigned the task of damaging the table. In this case, the work done by Z is known as negative work, as Z is lowering the work done by X and Y.

Consider one more example of Pipe and Cisterns. Suppose there are two pipes, C and D. C is used to fill the cistern, and D empties the cistern. It means that D is working against C. If a leak is developed in this cistern, then it will form a component of negative work; thus, it slows down the work done by C.

☛ Check CAT Syllabus for better understanding.

Time and Work Concepts for CAT - Work Equivalence

As per the concepts of Time and Work questions for CAT, the work done by people/cistern can be stated mathematically as follows:

Work done = Rate of Work x Time

Note the formula that is given below as well:

M1D1T1 = M2D2T2

Here: D= Days, M=Person Number, T=Hours

This equation is known as the formula of work equivalence for Time and Work CAT questions. 

Time and Work Concepts for CAT - Efficiency

As per the concept of CAT Time and Work Questions, the two variables are said to be inversely proportional if their product is always constant. If A is twice as good as B then A will take half the Time that B will take because efficiency and time required are inversely proportional.

If the efficiencies are in a ratio format, like M: N, then time will also be in a ratio format, N: M.

Types of Time and Work Questions for CAT

If you check CAT Previous Year’s Questions, you will know that there are some specific types of Time and Work CAT questions. The two most important types of CAT Time and Work questions are as follows:

  • Problem involving Group Efficiencies

In this type of question, the aspirant needs to look at the problem where the people having the same efficiencies are working in a group.

  • Problem involving Individual Efficiencies

In this type of Time and Work Questions for CAT, you have to look at the individual efficiencies that are required to perform work. The calculation is required to find the rate at which they can complete the whole work together.

Make a list of CAT Preparation Books. Solve multiple CAT Time and Work Questions regularly to understand the concept and improve the efficiency of solving them in the exam. 

Time and Work Questions for CAT PDF

The candidates, who are thinking to appear in the upcoming exam must practice CAT Time and Work Questions to grip on these questions. Click on the link below to download Time and Work CAT Questions.

Formula for Time and Work Questions for CAT

It is very important to know the shortcut formula tricks to solve CAT Time and Work Questions accurately. Note the below points for important formulas for Time and Work questions.

  • Rate of Work = 1 / Time Taken
  • Work Done = Time Taken × Rate of Work.
  • Time Taken = 1 / Rate of Work
  • Efficiency and Time are inversely proportional to each other.
  • If a piece of work is done in X number of days, then the work done in one day = 1/X
  • Total Wok Done = Number of Days × Efficiency
  • X: Y is the ratio of the number of men who are required to complete a piece of work, then the ratio of the time taken by them to complete the work will be Y:X
  • If x number of people can do W1 work, in D1 days, by working T1 hours each day and the number of people can do W2 work, in D2 days,  by working T2 hours each day, then the relation between them will be = (M1*D1*T1)/W1 = (M2-D2*T2)/W2

Download CAT Time and Work Questions with Solutions

Tricks to Solve Time and Work Questions for CAT

While solving CAT Time and Work Question, the aspirants must keep in mind the tricks that are given below.

  • Tip 1: Wages and Work Concept: The ratio of the wages of the people doing work is directly proportional to the efficiency ratio of the people.
  • Tip 2: The ratio is directly and inversely proportional to the work done and time, respectively as per the mathematical concept.
  • Tip 3: The time taken or the number of days that is required to complete the work by C and D both is equal to the cd/c+d.
  • Tip 4: If X can complete the total work in 15 days, then X will perform 1/15 part of the total work in 1 day.
  • Tip 5: If C is thrice as good as D, then we can write the following:
    • In a certain period of time, C will perform 3 times more work than B. The ratio of the work will be 3:1
    • For the same amount of work, D will take the time thrice as much as A takes. The ratio of time taken will be 1:3 

Go through the CAT Preparation Tips and be prepared for the upcoming exam. Along with the above-mentioned tips to solve Time and Work Questions for CAT, candidates can also solve puzzles for CAT exam to improve their analytical and reasoning skills. 

Sample Questions of Time and Work Questions for CAT

Question 1: A water tank has three taps: A, B, and C. A fills 4 buckets in 24 min, B fills 8 buckets in 1 hr, and C fills 2 buckets in 20 min. If all the taps are opened together, then a full tank is emptied in 2 hr. If a bucket contains 5 L of water, then what is the capacity of the tank?

(a) 120 L

(b) 240 L

(c) 180 L

(d) 60 L

Solution: The capacity of the bucket as mentioned in the question is 5 liters

So, tap A fills 20 liters of water in 24 min.

Tap B fills 40 liters of water in 60 min

Tap C fills 10 liters of water in 20 min

So, the work done by all the taps together in 2 hours 

= {(20/24*120)+(40/60*120)+(10/20*120)}

= 240

Answer: Thus, the capacity of the tank is 240 liters.

Question 2: A builder appoints three construction workers, Akash, Sunil, and Rakesh, to one of his sites. They take 20, 30, and 60 days respectively to do a piece of work. How many days will it take Akash to complete the entire work if he is assisted by Sunil and Rakesh every third day?

  1. 10 days
  2. 15 days
  3. 25 days
  4. 30 days

Solution: Total work done by Akash, Sunil and Rakesh in 1 day = {(1/20) + (1/30) + (1/60)} = 1/10 Work done by Akash in 2 days = (1/20) × 2 = 1/10

Work Done in 3 days (1 day of all three together + 2 days of Akash’s work) = (1/10) + (1/10) = 1/5

So, work done in 3 days = 1/5

Time taken to complete the work = 5×3 = 15

Answer: 15 Days

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  • As per the Exam Analysis, the Time and Work Questions for CAT is based on the basic mathematical concept. Work is basically the effort that is applied to perform or accomplish a task. For this, a certain amount of time (T) is required to complete a certain work (W). The number of units of work done per unit time is called the rate of work (R). Hence, Work (W) = RxT = Rate x Time

  • No, not at all. Basically, Time and Work Questions for CAT are tricky if you are not prepared well. So, the aspirants just need to prepare the basic formulas for Time and Work to ace these questions.

  • You need to clear the basic concepts of CAT Time and Work Questions first to prepare this. Always keep in mind that the wages ratio for the persons is directly proportional to the efficiency ratio of the persons. You can attend BYJU’S Exam Prep CAT Online Classes to clear your doubt with experts assistance.

  • As per expert analysis, the aspirants can expect 2-3 CAT Time and Work questions. These questions are a little tricky. So, you must be well-versed with all the basic formulas, tips and tricks to solve these questions accurately.

  • As per the expert analysis, the logical reasoning Puzzle for CAT is extremely beneficial to grasp the concepts in a simple way. It is recommended to learn the Time and Work Questions for CAT via the puzzle method. It is always fun and ensures long-lasting results as you easily develop a strong hold on concepts.

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