PPT: Time And Work | CSAT Preparation - UPSC PDF Download

 Page 1


Time and Work
Page 2


Time and Work
Introduction to Time and 
Work
Exam Significance
Time and Work is a crucial topic 
in competitive exams due to its 
widespread applications and 
significant weightage in 
assessment.
Core Focus
This topic deals with calculating 
the time taken by individuals or 
groups to complete tasks and 
measuring the efficiency of 
work done by each participant.
Problem Categories
Time and Work problems typically fall into two categories: 
determining the time required to complete an assigned job, and 
calculating the work completed within a specified time period.
Page 3


Time and Work
Introduction to Time and 
Work
Exam Significance
Time and Work is a crucial topic 
in competitive exams due to its 
widespread applications and 
significant weightage in 
assessment.
Core Focus
This topic deals with calculating 
the time taken by individuals or 
groups to complete tasks and 
measuring the efficiency of 
work done by each participant.
Problem Categories
Time and Work problems typically fall into two categories: 
determining the time required to complete an assigned job, and 
calculating the work completed within a specified time period.
What is Time & Work?
Work is defined as something which produces an effect 
or outcome, typically one that is desired or expected. 
The fundamental concept of Time and Work is built 
upon proportionality, similar to other arithmetic topics.
The key relationship to understand is that efficiency is 
inversely proportional to the time taken when the 
amount of work remains constant. This can be 
expressed mathematically as:
Efficiency ? 1/Time taken
Page 4


Time and Work
Introduction to Time and 
Work
Exam Significance
Time and Work is a crucial topic 
in competitive exams due to its 
widespread applications and 
significant weightage in 
assessment.
Core Focus
This topic deals with calculating 
the time taken by individuals or 
groups to complete tasks and 
measuring the efficiency of 
work done by each participant.
Problem Categories
Time and Work problems typically fall into two categories: 
determining the time required to complete an assigned job, and 
calculating the work completed within a specified time period.
What is Time & Work?
Work is defined as something which produces an effect 
or outcome, typically one that is desired or expected. 
The fundamental concept of Time and Work is built 
upon proportionality, similar to other arithmetic topics.
The key relationship to understand is that efficiency is 
inversely proportional to the time taken when the 
amount of work remains constant. This can be 
expressed mathematically as:
Efficiency ? 1/Time taken
Concept of Time & Work
1
Basic Formula
If a person can complete 
a task in 'n' days, then 
work done in 1 day = 1/n. 
This fraction represents 
the person's capacity and 
can be expressed as a 
percentage.
2
Work Completion
If an individual can 
complete 1/n work in 
one day, they will 
complete the entire task 
in n days. Here, we 
assume the total work is 
one unit.
3
Combined Work
If A can complete work in 'a' days and B in 'b' days, then 
their one day's work = 1/a and 1/b respectively. Working 
together, they complete 1/a + 1/b or (a+b)/ab work in one 
day.
Page 5


Time and Work
Introduction to Time and 
Work
Exam Significance
Time and Work is a crucial topic 
in competitive exams due to its 
widespread applications and 
significant weightage in 
assessment.
Core Focus
This topic deals with calculating 
the time taken by individuals or 
groups to complete tasks and 
measuring the efficiency of 
work done by each participant.
Problem Categories
Time and Work problems typically fall into two categories: 
determining the time required to complete an assigned job, and 
calculating the work completed within a specified time period.
What is Time & Work?
Work is defined as something which produces an effect 
or outcome, typically one that is desired or expected. 
The fundamental concept of Time and Work is built 
upon proportionality, similar to other arithmetic topics.
The key relationship to understand is that efficiency is 
inversely proportional to the time taken when the 
amount of work remains constant. This can be 
expressed mathematically as:
Efficiency ? 1/Time taken
Concept of Time & Work
1
Basic Formula
If a person can complete 
a task in 'n' days, then 
work done in 1 day = 1/n. 
This fraction represents 
the person's capacity and 
can be expressed as a 
percentage.
2
Work Completion
If an individual can 
complete 1/n work in 
one day, they will 
complete the entire task 
in n days. Here, we 
assume the total work is 
one unit.
3
Combined Work
If A can complete work in 'a' days and B in 'b' days, then 
their one day's work = 1/a and 1/b respectively. Working 
together, they complete 1/a + 1/b or (a+b)/ab work in one 
day.
Approaches
Percentage Approach
Instead of treating total work as 1 
unit, we can consider it as 100% of 
the work. If A completes work in 'a' 
days, A does 100/a % work daily. If B 
completes work in 'b' days, B does 
100/b % work daily. Together, they 
complete 100/a + 100/b % work 
each day.
Fraction Approach
When using fractions, we consider 
the total work as 1 unit. The daily 
work contribution is calculated as 
the reciprocal of days needed to 
complete the entire task 
independently.
Selection of Approach
The choice between percentage and 
fraction approaches depends on the 
problem's structure. Both methods 
yield identical results but might 
offer different levels of convenience 
for specific scenarios.