# Time and Work - Shortcuts and Tricks

Time and Work is an important chapter for bank exams. This post is a part of "Shortcut Techniques" series where I decided to share shortcut techniques related quantitative techniques that can be used in IBPS exam or any other competitive exam.

Time and work is an important topic in IBPS exams, including clerks, PO and specialist officers.

## Trick

One simple technique is using days in denominator while solving questions. For example, A can do a job in 3 days and B can do the same job in 6 days. In how much time they can do the job together.
Solution - 1/3 + 1/6 = 1/2, hence 2 days is the answer.

Examiner can set the question in opposite way and can ask you how much time A or B alone will take to complete the job. It is quite easy to calculate said question by putting values in the equation we arrived in above question.

You need to understand one simple concept - If A can do a job in 10 days then in one day A can do 1/10th of the job.

## Shortcut

Best trick that I use in exams myself is by finding the efficiency of workers in percent. If A can do a job in 2 days then he can do 50% in a day.
Number of days
required to complete the work
Work that can be done per dayEfficiency in Percent
n1/n100/n
11/1100%
21/250%
31/333.33%
41/425%
51/520%
61/616.66%
71/714.28%
81/812.5%
91/911.11%
101/1010%
111/119.09%

### Now let's solve questions with this trick

#### Question 1.

A take 5 days to complete a job and B takes 10 days to complete the same job. In how much time they will complete the job together?

Solution - A's efficiency = 20%, B's efficiency = 10%. If they work together they can do 30% of the job in a day. To complete the job they need 3.33 days.

#### Question 2.

A is twice as efficient as B and can complete a job 30 days before B. In how much they can complete the job together?
Solution - Let efficiency percentage as x
⇒ A's efficiency = 2x and B's efficiency = x
⇒ A is twice efficient and can complete the job 30 days before B. So,
⇒ A can complete the job in 30 days and B can complete the job in 60 days

⇒ A's efficiency = 1/30 = 3.33%
⇒ B's efficiency = 1/60 = 1.66%
⇒ Both can do 5% ( 3.33%  + 1.66% ) of the job in 1 day.
So the can complete the whole job in 20 days (100/5)

#### Question 3.

A tank can be filled in 20 minutes. There is a leakage which can empty it in 60 minutes. In how many minutes tank can be filled?

Solution -
Method 1
⇒ Efficiency of filling pipe = 20 minutes = 1/3 hour = 300%
⇒ Efficiency of leakage = 60 minutes = 100%

We need to deduct efficiency of leakage so final efficiency is 200%. We are taking 100% = 1 Hour as a base so the answer is 30 minutes.

Update - 09-09-2013 ( As Shobhna and Aswin are facing problem in solving this question, I am solving this question with the second method which is also very easy, hope this will make the solution lot easier.)

Method 2
⇒ Efficiency of filling pipe = 100/20 = 5%
⇒ Efficiency of leakage pipe = 100/60 = 1.66%
⇒ Net filling efficiency = 3.33%
So tank can be filled in = 100/3.33% = 30 minutes

You can change the base to minutes or even seconds.

You can solve every time and work question with this trick. In above examples, I wrote even simple calculations. While in exams you can do these calculations mentally and save lots of time.

You can find more tricks like this in quantitative aptitude section.

Comment below in case of any query, I promise to reply within 24 hours.

Update - Question requested by Chitra Salin

#### Question 4.

4 men and 6 women working together can complete the work within 10 days. 3 men and 7 women working together will complete the same work within 8 days. In how many days 10 women will complete this work?
Solution - Let number of men =x, number of women = y

⇒ Efficiency of 4 men and 6 women = 100/10 = 10%
⇒ so, 4x+6y = 10
Above equation means 4 men and 6 women can do 10% of the job in one day.

⇒ Efficiency of 3 men and 7 women = 100/8 = 12.5%
so, 3x+7y = 12.5

By solving both equations we get, x = -0.5 and y = 2

⇒ Efficiency of 1 woman(y) = 2% per day
⇒ Efficiency of 10 women per day = 20%
So 10 women can complete the job in 100/20 = 5 days

Update Question requested by Praisy

#### Question 5.

A and B together can complete a task in 20 days. B and C together can complete the same task in 30 days. A and C together can complete the same task in 30 days. What is the respective ratio of the number of days taken by A when completing the same task alone to the number of days taken by C when completing the same task alone?

Solution -
⇒ Efficiency of A and B = 1/20 per day = 5% per day ________________1
⇒ Efficiency of B and C = 1/30 per day = 3.33% per day______________2
⇒ Efficiency of C and A = 1/30 per day = 3.33% per day______________3

Taking equation 2 and 3 together
⇒ B + C = 3.33% and C + A = 3.33%
⇒ C and 3.33% will be removed. Hence A = B
⇒ Efficiency of A = B = 5%/2 = 2.5% = 1/40
⇒ Efficiency of C = 3.33% - 2.5% = 0.833% = 1/120
⇒ A can do the job in 40 days and C can do the job in 120 days he they work alone.
⇒  Ratio of number of days in which A and C can complete the job 1:3.

#### What's trending in BankExamsToday

Smart Prep Kit for Banking Exams by Ramandeep Singh - Download here

1. 1/6 - 1/2 = 1/4, = 40 minutes

1. is it rly useful

2. DO WE HAVE TRIGNOMENTRY IN EXAM

3. pls suggest shortcut method for time and distance.

2. Check detailed solution above

1. In this case :
Efficiency of A = B = 5%/2 = 2.5% = 1/20

100/2.5 = 40?

so efficiency of A should be 40 days..right?

2. Right, A can complete the job in 40 days.

3. Can u plz solve this question by efficiency method..and explain
A and B together can complete a task in 20 days. B and C together can complete the same task in 30 days. A and C together can complete the same task in 30 days. What is the respective ratio of the number of days taken by A when completing the same task alone to the number of days taken by C when completing the same task alone?

1. Solutions:

(A+B)=100/20=5%
(B+C)=100/30=3.33%
(A+C)=100/30=3.33%

(A+B+B+C+A+C)=11.66%
2(A+B+C)=11.66%
A+B+C=5.83%

(A+B+C)-(B+C)=5.83-3.33%
A=2.3%=100/2.3=43 DAYS

(A+B+C)-(A+C)=5.83-3.33%
B=2.3%=100/2.3=43 DAYS

(A+B+C)-(B+C)=5.83-5%
C=2.3%=100/0.83=120 DAYS

2. For the same u can do in the below process also
Let (A+B) do work in 'X' days
(B+C) - 'Y' days
(C+A) - 'Z' days
If to solve work done by A alone then use
A= 2xyz/(yz+zx-xy )
Put the above values in the formula
A= (2*20*30*30)/(900+600-600)=40
In the same way for
C= 2xyz/(xy+yz-zx)
then u will get C=120
So A:C = 40 : 120 = 1:3

4. can u plz explain the following with efficiency..i learned that method..so need to get answer in that method only...4 men and 6 women working together and completing a work within 10 days. 3 men and 7 women working together and completing the same work within 8 days. In how many days 10 women will complete this work

6. is there any way I can download these files and study without need of internet?

7. hw u get 30 minutes, can u pls explain, if 100% = 60 minutes, 300% = 20, minutes then 200% must be 40 minutes

1. if 60 mins is 100%..
then 200% means its half i.e 60/2= 30 mins and
300% means 60/3=20 mins
above I have devided by 2 and 3 because 200% is 2 times of 100% and IIIly 300% is 3 times of 100%..hope it is clear friend

8. Aswin read the question again. Don't stick to formuale.

If a pipe can fill the tank in 20 mins then in an hour it can fill the tank thrice soo efficiency is 300%

9. sir,
1/3 is 33.33% know..but u have mentioned 300% in that 3rd prob

11. its mt internet problem...can u mail me d answer? i prepare completely using ur site only...so efficiency method is not nywer else..it will be a great help..my id is chitra.salin@gmail.com..thank u

12. Please find the update at the end of article. I have solved the question for you.

13. hi..i m so sorry..i cant find the update..plz help

15. We should calculate per hour efficiency. In the above questions I have calculated per day efficiency, simply divide it by number of working hours in a day.

Once you know efficiency of a worker is x% per hour, then efficiency of 5 workers = 5x%

simply 100/5x = required hours.

Comment again if you have any problem.

16. What about questions involving men working particular hours of a day finish a job in say ten days. How many men should be employed that the job is finished in five days if they work say six hours a day.

17. refer http://www.bankexamstoday.com/2013/07/quantitative-aptitude-preparation.html

18. can you plz mail the quants tricks at my id
shilpachugh25@gmail.com

19. Please give some more examples based on these tricks

20. Find more shortcuts from Shortcuts section on top menu

21. 8 men complete work in 20 days. 8 women complete same work in 32 days in how many days will j 5 men and 8 women together complete same work? plz slove by efficiency method.

1. It is very difficult to solve this question by efficiency method, so I recommend you to solve this question by fraction method.

2. Answer is 16 days, get solutions below

22. Is the answer for the above query 12.3? If not kindly post the right answer.. Thanks!

1. Job need 160 Man days or 256 Women days.
⇒ 5 men can do the job in 32 days
⇒ 8 women can do the job in 32 days
⇒ if 5 men and 8 women work together, they can do 2/32 of the job per day
⇒ Hence they can complete he job n 16 days

23. i have a q can u plz give me the solution
2women nd 10 chilldren together take 8 days to complete a piece of work. how many days will 10 children alone take to complete piece of work if 8 women alone can complete piece of work in 6 days? ans is 12 days

1. Efficiency of 2 women and 10 children = 1/8 = 12.5% per day
Efficiency of 8 women = 1/6 = 16.66%
Efficiency of 1 women = 16.66%/2 = 2.08%

Deducting efficiency of 2 women from first statement = 12.5 - (2.08 * 2) = 8.33%
Efficiency of each child is 8.33% so they can complete he job in 12 days

2. If 8 women can complete work in 6 days then 1 women can complete it in (6*8=)48 days. So, effi of 1 woman is 1/48.
Now , from given data,
2 *(1/48)+10*(effi of 1 child)=1/8
Solving this, we get effi of 1 child is 1/120.
So, effi of 10 children becomes 1/12.
So, they can complete given work in 12 days

24. A alone can complete a work in 15 days and B alone in 20 days.starting with A they work on alternate days.The total work will be complete in how many days

1. Efficiency of A = 6.66%
Efficiency of B = 5%
Efficiency of A and B = 11.66%
After 8 days 11.66 * 8 = 93.28%
Work will be completed in approx 9 days

2. y 8days??? am not getting....

3. In first two days, A & B will complete (1/15+1/20=) 7/60 th part of work. So, in 16 day, they will complete 7/60*8= 56/60th part of work.
On next day means 17th day,
A will do 1/15 th of work. So,
56/60+ 1/15= 1.
So, wotk will complete on 17th day

4. why we are taking 8 cycle or 16 days , we can also take 5 cycle or 10 days.... so y we consider only 8 cycle???? make me understand

5. what is the correct answer (9 or 17)??

25. great work sir

26. A can do a piece of work in 7 days of 9 hours each and B can do it in 6 days 7 hours each. How long will they take to do it, working together 8 2/5 hours a day?

27. First of all, I appreciate and thank you for the good work you are doing...Its really great.

24 men can complete a work in 16 days and 32 women can complete the work in 24 days. 16 men and 16 women worked together for 12 days. How many men have to be added to complete the remaining work in 2 days? Please solve this using efficiency method

28. hello can u pls explain the last problem in detail
i dont understand the final step

29. hi sir sandeep here.here is my question.pls solve it by efficiency method.
A and B undertake to do a work for rupees 600. A can alone do it in 6 days while B alone can do it in 8 days.With the help of C,they finish it in 3 days.Find the share of each.

1. A alone can complete a work in 15 days and B alone in 20 days.starting with A they work on alternate days.The total work will be complete in how many days.

in this problem A and B work on alternate days but on working together. so the answer must be 17 days.
Solution: in 2 days A and B can do (1/15)+(1/20)=(7/60) work
in 16 days they can complete 8*(7/60)=56/60 work
remaining work is 4/60. 17th day is A's turn. so 4/60*15=1
so the whole work can be finished in 17 days.
Am i correct?

2. A in 6 days.
B in 8 days.
A+B+C in 3 days.
so C can do the work alone in 24 days.
so the ratio becomes (1/6):(1/8):(1/24) i.e 4:3:1
A's share 600*4/8=300
B's share 600*3/8=225
C's share 600*1/8=75

30. Q:- C takes 6 days to complete half of a work and D takes 5 days to complete 1/3rd of the same work. They take turns to complete the task. It C works for the first 4 days, in how many days will D complete the rest of the work without the help of C?

Ans:- Ramandeep Sir i am confused solving tthe equation plz solve ( my equation is C can do full work 8.33% D 6.66% Both C+D=15% now how can solve?

1. now C works for first 4 days so he will complete 8.33*4=33.33% work.
Now remaining work = 100-33.33 = 66.67
No of days D can complete work is 66.67/6.66 = 10 days

32. hmm thanks Mr. Raman

33. good night Raman, hope u dont get upset

anonymous :)

34. lol OMG what was the need to post those comments... Not done

35. hahahaha sardar ji my comments may not do good, what kind of approval is that???

1. don't why you are laughing.... share your joke with us :p

36. dont???? matlab may I not comment Sardar ji??

37. ek tu Sardaaaar ek mai sardar.... baaki sab bekaar :p

38. waiting for your replies :p sardar ji bas mere comments mat publish karo

1. Idiots are not allowed here, try to concentrate on your books. I don't think you deserve a job in a PSU bank. You don't even have guts to publish your name :p

39. i approve ur comments dont worry on that part, most welcome to post on ur own site

40. and also you have not answered my queries within 3 hours....

41. sir plez tell me in ibps clerk how many question to attempt in each subject to crack the exam
thanks...

42. sir plez tell me how many question to attempt in ibps clerk in each subject to crack the exam

43. Please provide the solution of the question:

x persons can finish a work in 30 days. If 6 persons are increased, work can be finished in 10 days less. then find the original persons

1. If X persons can do a job in 30 days then job per person will be 1/30X.
If the number of existing person (X) is increased by 6 the job will be finished in 10 days less means in 20 days.

Therefore :
X+6/30X = 1/20
on solving above equation the X will be 12. So, the number of orignal persons is 12

2. If X persons can finish a work in 30 days then work per person will be 1/30X.
If the number of persons are increased by 6 then there will be (X+6) persons and will take 10 days lesser that means 20 days (30-10).

We know that a person can do 1/30X work but X+6 persons will take 20 days.

Therefore :

X+6/30X = 1/20

on solving above equation X will be 12. Hence the original number of persons is 12.

Hope it helps :)

44. Please tell me how to solve 4x+6y=10,3x+7y=12.5 in brief.

1. LOAL bda wala ............
its linear eq in two variable.........
class IX maths dumbo

45. Sir can you provide some tricks for syllolism questions.

46. Sir in above q&answers I didn't understand the solving equations please explain the equation solving thanking you

47. 4 men and 6 women working together and completing a work within 10 days. 3 men and 7 women working together and completing the same work within 8 days. In how many days 10 women will complete this work.
-hello sir can you plz tell me how we get x= -0.5 and y= 2 i am not understand plz help...

1. sir you already solve this question above but i m not understand plzzzzzzzzzzz reply

48. hello friend, don't purchase bank exam study notes. its bakwas material. i purchased this notes some day before i got this material and after 2 hours i send mail to ramandeep singh for my refund money but he did not any reply now.

49. sir, Is time and work question method always give right answer..

1. Buddy its not a method, its just a logic that you have to understand which particularly this admin has not mentioned above. Its like if RAM do some work in 10 days then his one day work will be 1/10. So this is the way. Clear your logic and concepts first, dont just mug up the things as they are written, and instead of understanding concept and finding shortcuts on net, just take some good cat level book like Sarvesh k verma or arihant publication and devote your time. Even rome was not built in a day..:)

50. Good One. thanks for sharing

51. kindly solve this question.
14 person can complete a work in 16 days. 8 persons started the work 12 days after they started the work more persons joined them. how may days will they take to complete the remaining work?

1. Question is wrong.

More persons joined ? There should be specific number of persons who joined after 12 days.

2. ans is 1.75 days !
1 + 3/4 days will take to complete the work .
for calculation , drop a mail at gaurav.india579@gmail.com

3. ans is 1.75 days
for full detail on solving it , just mail me @
gaurav.india579@gmail.com

4. PLEASE provide calculations of it

52. Thank's sir u r grate...

53. TESTPANDA ROCKS

54. sir i have a doubt , i solve the below question using efficiency method but the answer is not right.can you pls solve this question using efficiency method?
6men & 8 boys can do a work in 10 days while 26 men &48 boys can do the same in 2 days,the time taken by 15 men & 20 boys doing the same work will be ___days?

55. today i tired that question and got the right answer using efficiency method and this method make me to solve the many question very easily.thank you sir

56. 40 men can cut 60 trees in 8 hour. if 8 men leave the job, how many trees will be cut in 12 hours. sir how can i do it by fraction or efficiency method

57. sir i have one problem in this question, please help me.... 40 men can cut 60 trees in 8 hour. if 8 men leave the job, how many trees will be cut in 12 hours ... how can i solve using efficiency method

58. A set of 10 pipes (say X)can fill 70% of a tank in 7 minutes.Another set of 5 pipes(say Y) fill 3/8 of the tank in 3 minutes.A third set of pipes(say Z) can empty 5/10 of the tank in 10 minutes.
If one pipe is added for set X and set Y and set Z's capacity is increased by 20% on its original value and all the taps are open at 2:58 p.m then at what time does the tank get filled?

59. It is very useful sir... Thank u so much sir:)

60. Great job friend. Thanks a lot ....... But what about discount for already registered users like me.

61. Hi sir Deepa here.here is my question.pls solve it.
A alone can complete a work in 15days and B alone in 20days.Starting with A,they work on alternate days.How many days will take to complete that work

62. hi sir, i have doubt...if 3 men and 4 boys can do work in 8 days.4 men and 4 boys can do a same work in 6 days.
then 2 men and 4 boys can finish it in how many days?

63. hello sir....i have a doubt...
A works twice as much as B. if both work together, they finish the job in 12 days. find in how many days A alone can do it?
20 days/ 24 days/ 18 days/ 36 days

64. I have a question, plz help me to solve it
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?

1. A's eff is 5% per day (100/20)
similarly B's eff is 10/3% per day
and C's eff is 5/3% per day
on 3rd day work done is- 15+ 10/3 +5/3 (A's 5% eff per day * 3 days= 15)
which is 20% work done.
its clear 100% work done=20% * 5
which is 3 days* 5 =15 days

hope its clear

65. Thank u so much Nivedita Mam I Got it

66. 6 men and 6 women can complete a work in 6 days, how many days required to complete same work for 15 men, as 9 women do the same work in 10 days?

67. A can work for 10 days,B in 12 days and C in 8 days.They all work for 2 days then C leaves and the remaining work is done by a and b. At what time do they finish the work?

68. A pipe can fill a tank in 8 hours and B tank can fill a tank in 6 hours.they both open to fill the tank but after 2 hours A is stopped,then how much total time take tp fill the total tank?

69. 4men and 7 boys can earn Rs. 3015 in 9 days.7men and 5 boys can earn Rs. 2835 in 7 days.In how many days will 8 men and 8 boys can earn Rs. 7280?

70. the equations are going to be like-
4x + 7y = 335 (3015/9, that gives us 1 day earning of 4 men and 7 boys)
7x + 5y = 405 (2835/7)

multiply 1st eq with 7 and 2nd eq with 4.
then the equations are-

28x + 49y = 2345
28x + 20y = 1620

which gives 29y = 725
y= 25
x= 40

no put values of x and y in 8x + 8y =7280/ no of days
that gives no of days = 14

71. can yu pls answer for this question!!
A can complete a job in 12 days, B can complete a job in 20 days, C can complete a job in 6 days. After 2 days C left the job and how many days more will taken by A and B to complete the job by working together?

1. A can complete a job in 12 days
which means A's efficiency is 25/3% (100/12)
similarly B's eff is 5% and C's eff is 50/3%

together their eff is-
25/3 + 5 + 50/3 = 30% per day
together they work fr 2 days, so 60% work is done.

after 2 days C leaves and 60% work is done and 40% work is remaining.
A and B eff together is 5+25/3 = 40/3 % per day
which means in 3 days A and B together can complete the remaining 40% work.

which means

72. A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is.? can we solve these kind of problems using efficiency method?

73. here is one more method, try this

total number of days/square of the no. of members .

so here 5+10/4 = 3.33... :)

74. A can do a piece of work in 14 days, B can do the same in 21 days, if A and B work together but 3 days before the completion of the work , A leaves off. the total no. of days to complete the work is?

75. all the best :)

76. A can do a piece of work in 24 days .if B is 60 % more efficient then A,then B can complete the work in

77. total work=(sum of two efficiency)*total time
Or
Total work=(product of two efficiency)*total time

1. 10 man can complete a work in 15 days..they started work and after 5 days 10 women joined them and work finished in 5 days..in how many days 25 women finish the same piece of work

78. A takes 6 hr less than together, B takes 1.5 hr less than toether. In how many hour thay can complete the work????

79. if A takes 8 hrs to complete a job and B takes 10 hrs to do the same work, how long would it take for both A and B to complete the work together but independently to do the same work?

80. एक टीम के ३० व्यक्ति द्वारा एक कार्य को ३६ दिनों में समाप्त करते है ,३० दिन बाद कुछ व्यक्ति और शामिल हो जाते है तो कार्य 2 दिन पहिले समाप्त हो जाता है, तो बढे हुए व्यक्ति यो की संख्या किंतनी है

81. Awesome. Thank you so much :)

82. A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?

83. SIR PLEASE PROVIDE TRIGONOMETRY SHORTCUTS

84. 2 Men & 3 women or 4 men can a work in 20 days.then in how many days 3 women and 3 men dothis work???
Plz tell with efficiency method

85. In a game of chess, a boy lost 3 rounds less than he won. he can score 4 points for a win and lost 2 points for a loss .how many rounds,in all ,have he played if his score is 46?
kindly solve this question.

1. He played 37 rounds.
20 won and 17 lost.
As I think

86. hey it was so help full

87. Hi
These r very useful ...thanks I want to understand in question 2 u have taken 30 days for A and 60 for B....where as it says A complete 30 days before ....if we take 90 n 60 days the answer will not be same

88. PLssssss solve this que given in RBI 2014
If 3 men and 4 women can complete a work in 20 days then in how many days the same work can be completed by 5 men and 7 women?

89. A can complete a piece of work in 40 days and B in 60 days. A worked alone for 4 days and them B completed the remaining work along with C in 36 days. in how many days can C work alone to complete the work ?

1. Work done by A= 1/40 per day. He worked for 4 days. So 1/40*4=1/10 work done.
So work to be done=9/10.
B can work 1/60 per day. So for 9/10 work he needs 9/10*60=54 days.
Now form the equation. B+C=1/36
1/54+c=1/36
So C= 1/108
for 9/10 work C needs 108 days so for 1 work he needs 108*1*10/9= 120 days.

90. A and B can do a work in 14 days and 25 days respectively. A started work and left after 3days , b immediately took over and worked till end .In how many days was the total work done ?

91. Raman sir can u pls place some tricks on alternate working days

92. three men a,b,c can working together can do a job in 6 hours less time than a alone,in 1 hour less time than b alone and in half the time needed by c when working alone.then a and b together can do the job in??

93. SIR I WANT TO GIVE UR NOTES BACK .HOW CAN DO THIS.

94. The first attempts at exams on my schools are as I've heird: 'recon missions' there should be a bigger reward for students who ace exams on their first try.

What most people don’t realize is that studying and learning should never be too difficult. I’m sure I don’t have to tell you what it’s like. You know the feeling: you go to class, get a ton of homework, then spend hours and hours reading over your notes, trying to memorize everything in a mad panic before your next exam.
Not only is this stressful, but studying this way is both time consuming and a huge waste of energy. But the good news is, studying doesn’t have to be this difficult.
In fact, if done correctly studying and learning should be a pleasurable experience. It shouldn’t be hard and it should probably take you less than half the time you’re already spending. So how is all this possible?

This video explains efficiënt studying:
Efficient studying