1.
Work
from Days:
If
A can do a piece of work in n days, then A's 1 day's work =

1

.

n

2.
Days
from Work:
If
A's 1 day's work =

1

,

then
A can finish the work in n days.

n

3.
Ratio:
If
A is thrice as good a workman as B, then:
Ratio
of work done by A and B = 3 : 1.
Ratio
of times taken by A and B to finish a work = 1 : 3.
4. No. of days = total work / work done
in 1 day
5. Relationship
between Men and Work
More men  can
do > More work
Less men  can
do > Less work
6. Relationship
between Work and Time
More work  takes>
More Time
Less work  takes>
Less Time
7. Relationship
between Men and Time
More men  can
do in > Less Time
Less men  can
do in > More Time
8. If
M_{1 }persons can do W_{1} work in D_{1} days and M_{2}
persons can do W_{2} work in D_{2} days, then
9. If
M_{1 }persons can do W_{1} work in D_{1} days for h_{1}
hours and M_{2} persons can do W_{2} work in D_{2} days
for h_{2} hours, then
Note: If
works are same, then M1D1h1 = M2D2h2
10. If
A can do a work in ‘x’ days and B can do the same work in ‘y’ days, then the
number of days required to complete the work if A and B work together is
11. If
A can do a work in ‘x’ days and A + B can do the same work in ‘y’ days, then
the number of days required to complete the work if B works alone is
For easily solving any question on work and time, one must have clear understanding of concepts. While searching google, I found this page:
ReplyDeletehttp://learnapti.com/NumericalAptitude/Timeandwork.aspx .
I found this quite useful, so i am sharing this with all of you.
very helpful,its time saving
Deletenice formulas.... really it will help me for my exmas.... amazing........
ReplyDeletevery understanding....
ReplyDeleteThanks. Compact and helpful.
ReplyDeleteHi, can u solve this question,
ReplyDelete" 12 men alone can complete a piece of work in six days, whereas 10 men and 21
women take three days to complete the same piece of work. In how many days
can 12 women alone complete the same piece of work? "
Let us assume a man can do 'x' units of work and a woman can do 'y' units of work per day.
DeleteSo total work done in 1st case = 12*6*x = 72x
Work done in 2nd case = 3*(10x + 21y) = 30x + 62y
In both the cases, work is same as mentioned in the problem.
=> 72x = 30x+62y
=> 42x = 62y => 2x = 3y
Let us assume, x as 3 and y as 2 to satisfy the above equation
Total work = 72*3 = 216
To complete 216 units of work by 12 women, they require 216/(12*2) = 9 days.
Work done in 2nd case = 3*(10x + 21y) = 30x + 62y ???
DeleteI hope u understand dear (21*3 is 63 not 62)
i dint understand y did u multiply 12*2 in d denominator can u pls explain me
Deletehere
DeleteW=MDH
W=216,M=12,D=?,H=y=2
so
Days=D=W/MH
D=216/12*2
so D=9 days
Totally wrong soln prabhath
DeleteThis comment has been removed by the author.
ReplyDeleteFirst i wanted to say thanks for easy understanding.But there is a small correction in the question no 11,
ReplyDeleteIf A can do a work in ‘x’ days and A + B can do the same work in ‘y’ days, then the number of days required to complete the work if B alone can do the work ??
Correct, Thanks for the correction..
Deleteplz help me out to solve the questions
ReplyDeleteif 9 men working 71/2 hrs a day can complete a work in 20 days,then in how many days will be taken by 12 men,working 6 hrs a day to finish the work?it is being given that 2 men of latter type works as much as 3 men of former type?
Given that 2 men of latter type works as much as 3 men of former type
Delete=> Let us assume former type completes 2 pieces of work while latter type completes 3 pieces of work each.
So work completed in 1st case is 9 * 15/2 * 20 * 2
If 'x' is the no. of days to complete work, work completed in 2nd case is 12 * 6 * x * 3
As the work is same in 2 cases,
9 * 15/2 * 20 * 2 = 12 * 6 * x * 3
=> x = 12.5 days
It is 71/2 hrs and the answer is given to be 121/2 in the solution.
Deleteplease help
Its not 71/2... its 7 (1/2)
DeleteThen the answer is not 121/2 .. its 12 (1/2) = 12.5
6 men and 8 boys can do a price of work in 10 days while 26 men and 48 boys finish it in 2 days. 15 men and 20 boys will finish it in ???
ReplyDeleteplzzz....tell off me how u solve it easily within few sec.
DeleteThis comment has been removed by the author.
Delete6 men + 8 Boys = 10 days, 26 men and 48 Boys = 2 days
ReplyDelete60 men + 80 Boys = 52 Men + 96 Boys
8 M = 16 B
1 Man = 2 Boys
15 M + 20 B = 30 B + 20 B = 50 Boys
6 men + 8 boys = 12 Boys + 8 Boys = 20 Boys = 10 Days
Boy Days
20 10
50 x
50x = 20* 10
x = 20*10/50 = 4 days.
Please solve this question
ReplyDeleteFather and mother can fill a water tank in 2 hours,Father and son in 2 and a 1/2 hours,Mother ans son in 3 hours.If all three work together in how may hours they can fill the Tank?
This comment has been removed by the author.
Delete2F+2M+2S = 2 + 2 1/2+ 3
DeleteF + M + S = ( 15/2 )/ 2
F + M + S = 15/2 this time to fill 3 tanks
ie F + M +S = fill a tank 15/2/3
the answer is  15/6 , 1 1/4 hours.
answer should be (60/37) hrs
Deletef+m fills 1 tank in 2hrs
Deleteso f+m fills1/2 tank in 1 hr
f+s fills 2/5 tank in 1 hr
m+s fills 1/3 tank in 1 hr
so in 1 hr 2(f+m+s)=1/2+2/5+1/3
f+m+s in 1 hr fills 37/60 tank
f+m+s fills 1 tank in 60/37hrs
didn't get.please explain as per question
DeletePlease Solve this question for me..
ReplyDeleteOne boy can deliver newspapers on his route ub 1x1/4 hours. Another boy who takes his place one day takes 15 minutes longer. How long would it take to deliver the papers if the two boys worked together?
I NEED THE SOLUTION URGENTLY :(
really helpful formulae..
ReplyDeletePlease help me solving this, A+B = 12 days, B+C = 10 days, C+A = 15 days. A alone in how many days? (please give step by step solution)
ReplyDelete2(A+B+C)=1/12+1/10+1/15.
DeleteFrom above equation we will get A+B+C=1/8.
Then for A's work=total work done by all memberswork done by B&C
=>A's 1days work=(1/8)1/10
=1/40.
So A can do the work in 40 days
THANK YOU IT WAS VERY USEFULL
ReplyDeleteKaran, Kabir and Kartik can together finish a project in 4 days. Karan by himself can do it in 12 days and kabir by himself can do it in 10 days. How many days will karthik take to finish the project alone?
ReplyDeletepleas reply
karan+kabir+karthik can finish 1 prjct in 4 days
Deletekaran+kabir+karthik can finish 1/4 prjct in 1 day
karan finish 1/12 prjct in 1 day
kabir finish 1/10 prjct in 1 day
karan+kabir finish 1/12+1/10=7/60prjct in 1 day
karthik alone can finish=(karan+kabir+karthik)(karan+kabir) prjct in 1 day=1/47/60=2/15prjct
so karthik takes 15/2 days to cmplt d prjct alon
thanks for your formula
ReplyDeletevery nice formulas
ReplyDeleteA can do a piece of work in 10 days and b in 30 days and c in 60 days. If A is assisted by B and C on alternate days, them in how many days the work gets completed?
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteA,B,C can do a work in 8,12,16 respectively. A & B continuing a work till 3 days then B leaves and C is replaced by B. Finally A and C can do a remaining work in how many days?
ReplyDelete24 men can complete a work in 16 days.The same work can be completed by 8 women in 72days,whereas 24 children take 32 days to complete. If 10 men 15 women and 24 children work together, in how many days can be completed
ReplyDeleteNice Shortcut methods to solve,
ReplyDeleteI Found one more link to solve Aptitude problems on time and work, tlwhis is also have excellent shortcut methods.
Click here to know shortcut methods
tqu for providing these type of formulas its very usefull
ReplyDeletePlease helo me to slove below mentioned problem....
ReplyDelete20 men can do a piece of work ib 15 days.one man started the work in the first day and after every day one more man joins the work... Its continued till the work is completed... Thn how many days till the work is completed????