Quantitative Notes on Time & Work (Part I)

By Neha Uppal|Updated : January 20th, 2021

On this day, we will share "Time & Work" topic with you. Time and Work is an important topic of the arithmetic section for Railways and SSC exams. We are sharing with you some important questions asked under Time and work topic along with various approaches that you can follow to solve these questions. We will continue this topic in various parts. In this first part, we will discuss the basic questions that are usually asked in this topic and how you can solve them using the normal as well as Shortcut approach.

On this day, we will share "Time & Work" topic with you. Time and Work is an important topic of the arithmetic section for Railways and SSC exams. We are sharing with you some important questions asked under Time and work topic along with various approaches that you can follow to solve these questions. We will continue this topic in various parts. In this first part, we will discuss the basic questions that are usually asked in this topic and how you can solve them using the normal as well as Shortcut approach.

After going through these questions, make sure that you practice the questions to you understand these concepts clearly. In case of any query, leave a comment and we will try to solve it for you.

Example 1

A takes 8 days to finish a piece of work. B takes 10 days to finish the same work. How long will it take to finish the work when both of them are working together?

Solution

Basic Approach:
Now for such questions, A’s 1 day work = 1/8
B’s 1 day work = 1/10
Work done by both A and B together in one day = 1/8 + 1/10 = 9/40
Hence, A and B together will finish the work in 40/9 days.

While taking exam, you can express the information provided in the undermentioned form so that it consumes less time and space.

Example 2

A takes 8 day to finish a piece of work. B takes 10 days to finish the same work. C takes 20 days to finish the work. How long will it take to finish the work when all are working together?

Solution

Example 3

A takes 8 day to finish a piece of work. B takes 10 days to finish the same work. C takes 20 days to finish the work. D takes 40 days to finish the work. How long will it take to finish the work when all of them are working together?

Solution

Example 4

B and C together can complete the work in 8 days. A and B together can complete the same work in 12 days while A and C together can complete it in 16 days.

Solution

(a) In how many days A, B and C together can complete the same work?

(b) In how many days A alone can complete the work?

(c) In how many days B alone can complete the work?

(d) In how many days C alone can complete the work?

Example 5

If A+B can do a work in 10 days and A alone can complete the same work in 15 days. Find the no. of days taken by B to complete the work alone?

Solution

Example 6

If A+B+C can do a work in 6 days, A+B can do a work in 8 days and and A+C can do a work in 10 days.

Solution

Example 7

Rohit can do a piece of work in 10 days, but with the help of Amit, he can do the same work in 6 days. In what time Amit can do the same work alone?

Solution

Example 8:

There are two gardeners A and B. Both plant some no. of trees in a garden in 10 days and 16 days respectively. In how many days both can complete the work together?

Solution:

Now let’s discuss this same question by a different approach.

When time taken by A and B respectively is given, we can find the ratio of efficiency of A and B by taking inverse of their time.

Let’s do some examples to calculate efficiency.

Example 9:

If A and B alone do the same work in 14 and 18 days respectively, then ratio of efficiency of A and B.

Solution:

Example 10 :

If A and B together complete the work in 10 days and B alone complete the same work in 15 days. In how many days can A alone complete the same work?

Solution:

Example: 11

A is thrice as good as workman as B. Together they can finish a work in 12 days. In how many days will A finish the same work alone?

Solution:

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Posted by:

Member since Oct 2018
4+ Years of experience as a mentor and content developer for SSC & Railways exam. Cleared various exams including SSC CHSL & SSC CGL exams.

write a comment

Tanu MishraJan 22, 2021

Thanks@Neha Uppal

Rohit PalJan 22, 2021

Very nice

SkmauryaJan 23, 2021

Hi

Bubai kumarJan 23, 2021

Where is the 2nd part ma'm

Raju Kumar GuptaJan 23, 2021

Sir hindi question

DeepikaJan 24, 2021

Nice

Kurma RaoJan 24, 2021

Tq

PraveenJan 24, 2021

How to calculate 40

Sukhjinder SinghJan 24, 2021

Thanku mam

Rajni BhargavJan 25, 2021

It was very helpful...thank you very much
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