Time and work

Hi friends,
I am happy to share this because it is my first post on aptitude.The solutions are look like big but after reading this it helps for exam preparation in simple way.Hope it helps………

Important Concepts in Time and Work:

If (a person) able to do 1work in “n” days,
                then (a person   1day work)=[1/n].
If (a person 1day work )=[1/n],
               then(a person) finish the work in “n days” .

Explaining  Time and Work with example:

Consider kannan(a person) able to do 1work in 1 day.Then kannan able to finish 5works in 5 days.But if1 work in 5 days means it is 1/5 as per concept.
Consider kavi able to do half work(i.e 1/2)  in 1 day.Then kavi able to finish 1 work in 2 days.So kavi able to finish 5 works in 10 days.But   if 1 work in 10days means it is 1/10 as per concept.

Kannan	Kavi
1st day = 1 work 2nd day = 1 work 3rd day= 1work 4th day= 1 work 5th day= 1 work	1st day = 1/2 work 6th day = 1/2 work 2nd day = 1/2work 7th day = 1/2 work 3rd day= 1/2work 8th day = 1/2 work 4th day= 1/2 work 9th day = 1/2 work 5th day= 1 /2work 10th day = 1/2 work
Total=5 works in 5 days	Total=5 work in 10 days

Why I am mentioning the above ?
Note that if  the ability of a person ability is less to finish the work then the days to finish the work wiil be more.

Some tips on Time and Work:

Try to convert the days into (a person 1day work)=[1/n].It will be mostly needed step in maximum problems in this type.

Problem on Time and Work:

Question:

A and B together can complete a piece of work in 4 days.If A alone can complete the same work in 12 days,in how many days can B alone complete that work?

Solution:

It was given that ,
A+B=4days ---------------------------------------------------------------->[Here and means +]
A=12days alone to  finish work
Therefore (A+B)one  day work------------------------------------------>[As given in concept]
W_(A+B)       =1/4 ------------------------------------------------------------>[Workdone   by  A+B in 1day]
W_A                =1/12----------------------------------------------------------->[Work done by   A alone in 1day]
Therefore,
W_{(A+B)  =}    W_A   + W_B  
1/4         =     1/12 +W_B
W_B           =    1/4  _  1/12-------------------------------------------------->[Work done by B alone in 1day]
W_B                 =1/6
Finally ,B alone can  complete the work in 6 days.

Anything  wrong? Comment below…

Also See:

Problem on Time and Work
Different Problem on Time and Work