Table of Contents

**Time and Work**

## Time & Work- Importance

**Time &Work**though the concept of Time & Work remains the same. It is the most common topic which is asked in every Government Exam. Candidates can expect to see Time & Work questions in data sufficiency and data interpretation also for which it becomes crucial to understand the basic concept of Time & Work. So, in this article, we have covered the Time and Work formulas as well as Time and Work Tricks so that candidates can score more marks in less time.

**Time And Work Formulas & Tricks**

When you know Time and Work formula, you can completely link that formula to the solution as soon as you read the question. Knowing Time & Work tricks will also help you solve the questions in a few seconds and thus saving your time for other sections. You can find Time & Work formulas along with important Time & Work Tricks below.

**When work is the same.**

**Time∝1/Efficiency**

**If A can do a piece of work in n days.**

**Then, per day working efficiency of A = 1/n**

**If the working efficiency of A & B is → x: y.**

**Then, the time taken by A & B to finish the work is in the ratio → y: x**

- If A can do a piece of work in x days and B can do a piece of work in y days, then both of them working together will do the same work in

**XY/(x+y) days**

__Explanation__**Q. A can finish a piece of work by working alone in 6 days and B, while working alone, can finish the same work in 12 days. If both of them work together, then in how many days, the work will be finished?**

**Sol.**x = 6, y = 12

**If A, B & C will work alone and can complete a work in x, y, and z days, respectively, then they will together complete the work in**

**XYZ/(xy+yz+zx)**

__Explanation__

**Q. A, B, and C can complete a piece of work in 10, 15, and 18 days, respectively. In how many days would all of them complete the same work working together?**

**Sol.**x = 10 days, y = 15 days & z = 18 days

**Two persons A & B, working together, can complete a piece of work in x days. If A, working alone, can complete the work in y days, then B, working alone, will complete the work in**

**⇒xy/(y-x)**

__Explanation__

**Q. A and B working together take 15 days to complete a piece of work. If A alone can do this work in 20 days, how long would B take to complete the same work?**

**Sol.**x = 15, y = 20

**Click Here to Attempt More Questions From Quantitative Aptitude For SSC CGL **

**If A & B working together can finish a piece of work in x days, B & C in y days, C & A in z days. Then, A + B + C working together will finish the job is**

**⇒2xyz/(xy+yz+zx)**

__Explanation__

**Q. A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. How long would they take to complete the full work together?**

**Sol.**x = 12 days, y = 15 days, z = 20 days

**If A can finish a work in x days and B is k times more efficient than A, then the time taken by both A and B, working together to complete the work is**

**x/(1+k)**

__Explanation__

**Q. Harbans Lal can do a piece of work in 24 days. If Bansi Lal works twice as fast as Harbans Lal, how long would it take to finish the work working together?**

**Sol.**x = 24, k = 2

**If A & B working together can finish a work in x days & B is k times more efficient than A, then the time taken by,**

**Working Alone will take ⇒ (k + 1) x**

**B working Alone will take ⇒ ((k+1)/k)x**

__Explanation__

**Q. A and B together can do a piece of work in 3 days. If A does thrice as much work as B in a given time, find how long A alone would take to do the work.**

**Sol**. x = 3, k = 3

**If A working Alone takes a day more than A & B, & B working Alone takes b-days more than A & B. Then,**

**The number of days, taken by A & B working together to finish a job is = √ab**

__Explanation :__

**Q. An alone would take 8 hrs more to complete the job than if both A and B worked together. If B worked alone, he took 41/2 hrs more to complete the job than A and B worked together. What time would they take if both A and B worked together?**

**Sol.**a = 8, b = 9/2

**Q. 4 men and 5 boys can do a piece of work in 20 days while 5 men and 4 boys can do the same work in 16 days. In how many days can 4 men and 3 boys do the same work?**

a. 10 days

b. 15 days

c. 20 days

d. 25 days

**Correct answer:**(c)

**Sol: **Assume 1 man’s 1 day work = x & 1 boy’s 1 day work = y

From the given data, we can generate the equations as : 4x + 5y = 1/20 —(1) & 5x + 4y = 1/16 —(2)

By solving the simultaneous equations (1) & (2),

x = 1/ 80 & y = 0

Therefore, (4 men + 3 boys ) 1 day work = 4 x 1 + 3 x 0 = 1

80 20

Thus, 4 men and 3 boys can finish the work in 20 days.

**Q. Sonal and Preeti started working on a project and they can complete the project in 30 days. Sonal worked for 16 days and Preeti completed the remaining work in 44 days. How many days would Preeti have taken to complete the entire project all by herself? **

- 20 days
- 25 days
- 55 days
- 46 days
- 60 days

**Correct answer: **60 days

**Sol: **Let the work done by Sonal in 1 day be x

Let the work done by Preeti in 1 day be y

Then, x+y = 1/30 ——— (1)

⇒ 16x + 44y = 1 ——— (2)

Solving equations (1) and (2),

x = 1/60

y = 1/60

Thus, Preeti can complete the entire work in 60 days

**Q. P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both p and Q work together, working 8 hours a day, in how many days can they complete the work?**

**Correct Answer: 60/11**

**Sol: **P can complete the work in (12 x 8) hrs = 96 hrs

Q can complete the work in (8 x 10) hrs=80 hrs

Therefore, P’s 1 hour work=1/96 and Q’s 1-hour work= 1/80

(P+Q)’s 1 hour’s work =(1/96) + (1/80) = 11/480. So both P and Q will finish the work in 480/11 hrs

Therefore, Number of days of 8 hours each = (480/11) x (1/8) = 60/11

**Q. (x-2) men can do a piece of work in x days and (x+7) men can do 75% of the same work in (x-10)days. Then in how many days can (x+10) men finish the work?**

**Correct Answer:** **12 days**

**Sol: **34×(x−2)x=(x+7)(x−10)34×(x-2)x=(x+7)(x-10)

⇒x2−6x−280=0⇒x2-6x-280 =0

=> x= 20 and x=-14

so, the acceptable value is x=20

Therefore, Total work =(x-2)x = 18 x 20 =360 unit

Now 360 = 30 x k

=> k=12 days

**Q. A is thrice efficient as B and C is twice as efficient as B. what is the ratio of several days taken by A, B, and C, when they work individually?**

**Correct Answer:** **2:6:3**

**Sol:**

A: B: C

The ratio of efficiency is 3: 1: 2

The ratio of No.of days 1/3: 1/1: 1/2

or 2: 6 : 3

Hence A is correct.

### Time and Work FAQs

**Q. How is Time-related to Work?**

Ans: Time is directly proportional to work, the proportionality constant is known as Efficiency.

**Q. How can I score well in Time & Work topic?**

Ans: Clear your basic concepts of Time and Work and practice as many questions as you can to score well on this topic.

**Q. What is the weightage of Time and Work in different Government Exams?**

Ans: Usually 5-10% of questions are asked about this topic in different competitive exams.

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