Time and Work
This chapter is easiest chapter for the students. Even an
average student can perform better than in other chapters.
- Concept of efficiency is basically involve in this chapter.
Work is directly related with time. If a particular person
or machine works for more time then more work will be done and if it devotes
less then it yields less work i.e. output
of a machine or person is directly proportional to time, it provided that
he/she maintains his/her efficiency during the work.
CONCEPT OF EFFICIENCY
Let a person can complete a particular work in 2 days then
we can say that each day he does half of the work or 50% work each day. Thus his/her efficiency is 50% per day.
Efficiency generally
considered with respect to time. The time can be calculated either in days,
hrs, minutes or months etc.
So, if a person completes his work in 4 days, then his
efficiency (per day) is 25%. Since every day he work 1/4th of the total work (i.e. 25% of the
total work).
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No. of days/hrs required to work
in 1 day/hrs Percentage
efficiency
complete the whole work
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n
1/n 100/n
1
1/1
100%
2
1/2
50%
3 1/3 33.33%
4 1/4 25%
5
1/5 20%
6
1/6
16.66%
7 1/7
14.28%
8
1/8 12.5%
9
1/9
11.11%
10
1/10 10%
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Unitary
Method
- If a person can complete a work in n days then his one day's work = 1/n
- This one day's work in terms of percentage is called his efficiency.
- Also, if a person can complete 1/n work in one day, then he can complete the whole work in n days.
- A person can complete his work in n days, then his one day's work = 1/n, his % efficiency = 100/n.