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PPT: Time & Work

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Time and Work
Time and 
Work: 
Complete 
CA T Guide
Fundamentals
Units, rates and basic 
formulas
Work Problems
Individual and 
combined worker 
scenarios
Pipes & Cisterns
Inlet, outlet and leak 
problems
Speed & Time
Time-saving 
techniques and 
shortcuts
Page 2


Time and Work
Time and 
Work: 
Complete 
CA T Guide
Fundamentals
Units, rates and basic 
formulas
Work Problems
Individual and 
combined worker 
scenarios
Pipes & Cisterns
Inlet, outlet and leak 
problems
Speed & Time
Time-saving 
techniques and 
shortcuts
Understanding Work and Its Measurement
What is Work?
Work is any task that can 
be completed in a 
measurable amount of 
time. In mathematics, we 
typically consider work as a 
unit quantity that equals 1.
Key Principle
Work is always constant. 
What varies is the time 
taken and the rate of work 
(efficiency) of different 
workers.
Fundamental 
Relationship
W o r k = R a t e ×
T i m e
Page 3


Time and Work
Time and 
Work: 
Complete 
CA T Guide
Fundamentals
Units, rates and basic 
formulas
Work Problems
Individual and 
combined worker 
scenarios
Pipes & Cisterns
Inlet, outlet and leak 
problems
Speed & Time
Time-saving 
techniques and 
shortcuts
Understanding Work and Its Measurement
What is Work?
Work is any task that can 
be completed in a 
measurable amount of 
time. In mathematics, we 
typically consider work as a 
unit quantity that equals 1.
Key Principle
Work is always constant. 
What varies is the time 
taken and the rate of work 
(efficiency) of different 
workers.
Fundamental 
Relationship
W o r k = R a t e ×
T i m e
Core Formulas and Relationships
Basic Work Formula
W o r k = 
T i m e
1
If A completes work in 'n' days, A's rate of work =  work per day 
n
1
Combined Work Rate
C o m b i n e d  R a t e = R a t e +
A
R a t e +
B
R a t e +
C
...
When workers work together, their individual rates get added
Time for Combined Work
T i m e = 
C o m b i n e d  R a t e
1
Reciprocal of combined rate gives time to complete work together
Page 4


Time and Work
Time and 
Work: 
Complete 
CA T Guide
Fundamentals
Units, rates and basic 
formulas
Work Problems
Individual and 
combined worker 
scenarios
Pipes & Cisterns
Inlet, outlet and leak 
problems
Speed & Time
Time-saving 
techniques and 
shortcuts
Understanding Work and Its Measurement
What is Work?
Work is any task that can 
be completed in a 
measurable amount of 
time. In mathematics, we 
typically consider work as a 
unit quantity that equals 1.
Key Principle
Work is always constant. 
What varies is the time 
taken and the rate of work 
(efficiency) of different 
workers.
Fundamental 
Relationship
W o r k = R a t e ×
T i m e
Core Formulas and Relationships
Basic Work Formula
W o r k = 
T i m e
1
If A completes work in 'n' days, A's rate of work =  work per day 
n
1
Combined Work Rate
C o m b i n e d  R a t e = R a t e +
A
R a t e +
B
R a t e +
C
...
When workers work together, their individual rates get added
Time for Combined Work
T i m e = 
C o m b i n e d  R a t e
1
Reciprocal of combined rate gives time to complete work together
Solved Example: Two Workers
Problem Statement
Ram can complete a piece of work in 12 
days, whilst Shyam can complete the 
same work in 18 days. How many days will 
they take to complete the work if they 
work together?
Step-by-Step Solution:
Ram's rate of work =  work per day 1. 
12
1
Shyam's rate of work =  work per day 2. 
18
1
Combined rate = 3. +
12
1
 
18
1
Mathematical Calculation:
C o m b i n e d  r a t e = +
12
1
 
18
1
= =
36
3 + 2
 
36
5
Final Answer
T i m e = =
C o m b i n e d  r a t e
1
 =
5
36
7.2  d a y s
Alternative Method: 
Use the formula  where a and b are individual 
times.
 
a+ b
a b
 =
12 + 18
12 × 18
 =
30
216
7.2  d a y s
Page 5


Time and Work
Time and 
Work: 
Complete 
CA T Guide
Fundamentals
Units, rates and basic 
formulas
Work Problems
Individual and 
combined worker 
scenarios
Pipes & Cisterns
Inlet, outlet and leak 
problems
Speed & Time
Time-saving 
techniques and 
shortcuts
Understanding Work and Its Measurement
What is Work?
Work is any task that can 
be completed in a 
measurable amount of 
time. In mathematics, we 
typically consider work as a 
unit quantity that equals 1.
Key Principle
Work is always constant. 
What varies is the time 
taken and the rate of work 
(efficiency) of different 
workers.
Fundamental 
Relationship
W o r k = R a t e ×
T i m e
Core Formulas and Relationships
Basic Work Formula
W o r k = 
T i m e
1
If A completes work in 'n' days, A's rate of work =  work per day 
n
1
Combined Work Rate
C o m b i n e d  R a t e = R a t e +
A
R a t e +
B
R a t e +
C
...
When workers work together, their individual rates get added
Time for Combined Work
T i m e = 
C o m b i n e d  R a t e
1
Reciprocal of combined rate gives time to complete work together
Solved Example: Two Workers
Problem Statement
Ram can complete a piece of work in 12 
days, whilst Shyam can complete the 
same work in 18 days. How many days will 
they take to complete the work if they 
work together?
Step-by-Step Solution:
Ram's rate of work =  work per day 1. 
12
1
Shyam's rate of work =  work per day 2. 
18
1
Combined rate = 3. +
12
1
 
18
1
Mathematical Calculation:
C o m b i n e d  r a t e = +
12
1
 
18
1
= =
36
3 + 2
 
36
5
Final Answer
T i m e = =
C o m b i n e d  r a t e
1
 =
5
36
7.2  d a y s
Alternative Method: 
Use the formula  where a and b are individual 
times.
 
a+ b
a b
 =
12 + 18
12 × 18
 =
30
216
7.2  d a y s
Work and Efficiency Concepts
1
Efficiency Definition
Efficiency is the rate at which work is completed. If A is twice as efficient as B, then A 
completes work in half the time that B takes.
2
Efficiency Relationship
If efficiency ratio is , then time ratio is  (inverse relationship) m : n n : m
3
Practical Application
Higher efficiency means less time required. This concept helps solve problems involving 
workers with different skill levels.
Key Insight: Efficiency and Time have an inverse relationship. Double efficiency means 
half the time!
Read More

FAQs on PPT: Time & Work

1. What is the concept of Time and Work in mathematics?
Ans. The concept of Time and Work refers to the relationship between the amount of work done, the time taken to complete that work, and the efficiency of the individuals or machines performing the work. It is often expressed with the formula: Work = Rate × Time, where Rate is the efficiency of work done per unit time.
2. How are efficiencies of multiple workers combined in Time and Work problems?
Ans. When multiple workers are involved in a task, their efficiencies are added together to determine the total work rate. For example, if Worker A can complete a task in 6 hours and Worker B can do it in 4 hours, their combined work rate can be calculated as follows: A's rate = 1/6 (work per hour) and B's rate = 1/4. The total rate becomes (1/6 + 1/4) = 5/12, meaning together they can complete the task in 12/5 hours.
3. What is the significance of the unit of work in Time and Work problems?
Ans. The unit of work is crucial in Time and Work problems as it standardizes how work is measured. Common units include jobs or tasks completed. Understanding the unit helps in calculating the total work done, the time taken to complete a job, and the individual contributions of workers in collaborative tasks.
4. Can you explain the concept of 'Work Done' and how it is calculated?
Ans. Work Done is defined as the amount of work completed by a worker or a group of workers over a specific period. It can be calculated using the formula: Work Done = Efficiency × Time. For instance, if a worker has an efficiency of completing 1/8 of a task per hour and works for 4 hours, the work done would be (1/8) × 4 = 1/2 of the task.
5. What are some common types of Time and Work problems that are asked in competitive exams?
Ans. Common types of Time and Work problems in competitive exams include finding the time taken to complete a task by multiple workers, calculating the efficiency of workers when given different time frames, and determining how long it will take to complete a task if a portion of it has already been completed. Other variations include problems involving the replacement of workers and the completion of tasks with varying efficiencies.
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