TIME AND WORK

  1. TIME: Means time for completing a job or time actually worked.
  2. WORK: Means the amount of job assigned or the amount of job actually done.

Results

#1. 4 men and 6 women can complete a work in 8 days , while 3 men and 7 women can complete it in 10 days . In how many days will 10 women complete it ?

4 men and 6 women can complete a work in 8 days , while 3 men and 7 women can complete it in 10 days . In how many days will 10 women complete it ?

1 man’s 1 day’s work = x

1 women’s 1 day’s work =y

Then , 4x add 6y = 1/8 and 3x add 7y = 1/10

x = 11/400 , y = 1/400

1 woman’s 1 days work = 1/400

: 10 woman’s 1 day’s work = ( 1/400 * 10 )

= 1/40

= 40

hence , 10 woman will complete the work in 40 days

#2. If 2 men and 16 boys can do a piece of work in 5 days; 10 men and 24 boys can do it in 4 days, then the ratio of the daily work done by a man to that of a boy is :

If 2 men and 16 boys can do a piece of work in 5 days; 10 men and 24 boys can do it in 4 days, then the ratio of the daily work done by a man to that of a boy is :

1 man’s 1 day’s work=x

1 boy’s 1 days work= y

12x plus 16y=1/5

13x plus 24 y= 1/4

x= 1/100

y= 1/200

required ratio = x : y

= 1/100 : 1/200

= 2 : 1

#3. 10 women can complete a work in 7 and 10 children take 14 days to complete the work how many days will 5 women and 10 children take to complete the work?

10 women can complete a work in 7 and 10 children take 14 days to complete the work how many days will 5 women and 10 children take to complete the work?

1 woman’s 1 day’s work =1/70

1 child’s 1 day’s work =1/140

(5 woman plus 10 children)’s 1 day’s work = (5/70 plus 10/140)

= ( 1/14 plus 1/14)

1/7

#4. A alone can complete a work in 16 days and B alone in 12 days. Starting with A, they work on alternate days. The total work will be completed in :

A alone can complete a work in 16 days and B alone in 12 days. Starting with A, they work on alternate days. The total work will be completed in :

(A plus B )’s 2 days work =(1/16 plus 1/12) = 7/48

work done in 6 pairs of days = (7/48* 6)=7/8

remaining work = (1- 7/8)=1/8

work done by A on 13th day= 1/16

remaining work = ( 1/8-1/16)

=1/16

On 14th day it is B’s turn

1/12 work is done by B in 1 day 1/16 work is done byB in (12*1/16)

=3/4 days

total time = 13 3/4 days

#5. 12 men complete a work in 9 days . After they have worked for 6 days more men join them. How many days will they take to complete the remaining work?

12 men complete a work in 9 days . After they have worked for 6 days more men join them. How many days will they take to complete the remaining work?

1 man 1 day’s work = 1/108

12 men 6 day’s work = (1/9 * 6) = 2/3

remaining work = ( 1-2/3)=1/3

18 men’s 1 day’s work (1/108*18)=1/6

1/6 work is done by them in 1 day

1/3 work is done by them in ( 6*1/3)

=2 days

 

#6. Kim can do a work in 3 days while David can do the same work in 2 days. Both of them finish the work together and get Rs. 150. What is the share of Kim ?

Kim can do a work in 3 days while David can do the same work in 2 days. Both of them finish the work together and get Rs. 150. What is the share of Kim ?

Kim’s wages : David’s wages = Kim’s 1 days work : David 1 day’s wrok

=1/3 : 1/2 = 2 : 3

Kim share = Rs (2/5 * 150)

=Rs. 60

#7. A does 4/5 of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

A does 4/5 of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

whole work is done by A in ( 20 * 5/4)=25 days

(1-4/5)

1/5 work is done by A and B in 3 days

whole work will be done by A and B in 3* 5 = 15 day

A’s 1 days work = 1/25

( A plus B ) 1 days work = 1/15

B’s days work = (1/15- 1/25)

= 4/150

=2/75

37 1/2 days

#8. X can do a piece of work in 40 days. He work at it for 8 days and then y finished it in 16 days. How long will they together take to complete the work

X can do a piece of work in 40 days. He work at it for 8 days and then y finished it in 16 days. How long will they together take to complete the work

work done by X in 8 days = ( 1/40*8) =1/5

remaining work =(1-1/5)=4/5

work is done by Y in 16 days

whole work will be done by Y in ( 16*5/4)= 20 days

X’s 1 days work = 1/40

y’s 1 days work = 1/20

( X plus Y ) 1 days work = ( 1/40 plus 1/20)

=3/40

40/3 = 13 1/3 days

#9. A can finish a work in 24 days, B in 9 days and C in 12 days. B and C start the work but are forces to leave after 3 days. The remaining work done by A in :

A can finish a work in 24 days, B in 9 days and C in 12 days. B and C start the work but are forces to leave after 3 days. The remaining work done by A in :

(B Plus C) ‘s 1 days work = (1/9 plus 1/12) =7/36

work done by B and C in 3 days = ( 7 /36 *3)= 7/12

remaining work = (1-7/12)=5/12

1/24 work is done by A in 1 day

5/12 work is done by A in ( 24* 5/12)

= 10 days

#10. A can do a work in 15 days and B in 20 days, If they work on it together for 4 days then ta fraction of the work that is left is :

A can do a work in 15 days and B in 20 days, If they work on it together for 4 days then ta fraction of the work that is left is :

A’s 1 days work = 1/15

B’s 1 days work =1/20

(A plus B )’s 1 days work = ( 1/15 plus 1/20 )

= 7/60

(A plus B )’s 4 days work = ( 7/60 * 4 )

= 7/15

remaining work = ( 1- 7/15)

= 8/15

#11. A is 30 % more efficient then B; how much time will they , working together, take to complete a job which A alone could have done in 23 days :

A is 30 % more efficient then B; how much time will they , working together, take to complete a job which A alone could have done in 23 days :

Ratio of time taken by A and B = 10: 13

suppose B taken X days to do the work

10 : 13 :: 23 : x

X= (23* 13 / 10)

X= 299/10

A’s 1 days work = 1/23

B’s 1 days work = 10 / 299

(A plus B ) as 1 days work = (1/23 plus 10/ 299)

= 23/299

=1/13

A and B together can complete that  job in 13 days

#12. A work twice as fast as B; if B can complete a work in 12 days independently the number of days in which A and B can together finish the work is :

A work twice as fast as B; if B can complete a work in 12 days independently the number of days in which A and B can together finish the work is :

A and B = 2: 1

so ratio of time taken = 1 : 2

A’s 1 day’s work =1/6

B’s 1 days work = 1/12

(A plus B )’s 1 days work = ( 1/6 plus 1/12)

= 3/12

= 1/4

=4

A and B together can finish the work is 4 days

#13. A and B can do a work in 8 days B and C can do the same work in 12 days A, B and c together can finish it in 6 days A and C together will do it in :

A and B can do a work in 8 days B and C can do the same work in 12 days A, B and c together can finish it in 6 days A and C together will do it in :

(A plus B plus C )’s 1 day work =1/6

( A plus B )’s 1 days work = 1/8

( B plus C )’s 1 days work = 1/12

(A plus c )’s 1 days work = (2* 1/6)-(1/8 plus 1/12 )

= (1/3-5/24)

= 3/24

=1/8

A and C together will do the work in 8 days

#14. A and B can do a work in 12 days B and C in 15 days C and A in 20 days if A, B , C work together they will complete the work in :

A and B can do a work in 12 days B and C in 15 days C and A in 20 days if A, B , C work together they will complete the work in :

(A Plus B)’s 1 days work = 1/12

( B plus C )’s 1 days work = 1/15

(A plus C)’s 1 days work = 1/20

Adding to both number= 2( A plus B plus C)’s 1 days work = (1/12 plus 1/15 plus 1/20)

= 12/60

= 1/5

( A plus B plus C)’s 1 days work= 1/10

A ,B and C together can complete the work in 10 days

#15. A man can do a piece of work in 5 days but with help of his son he can do it in 3 days in what time son do it alone ?

A man can do a piece of work in 5 days but with help of his son he can do it in 3 days in what time son do it alone ?

son’s a 1 days work = ( 1/3-1/5)

= 2/15

the son can do the work in 15/2= 7 1/2 days

#16. A, B and C can complete a piece of work in 24,6 and 12 days respectively working together they will complete the same work in :

A, B and C can complete a piece of work in 24,6 and 12 days respectively working together they will complete the same work in :

( A plus B Plus C)’s 1 days work = (1/24 plus 1/6 plus 1/12)

= 3/24

A,B and C together will complete the job in 24/7

= 3 3/7 days

#17. Work a taken 8 hours to do a job, worker B taken 10 hours to the same job how long should it take both A and B, working together what independently to do in the same job ?

Work a taken 8 hours to do a job, worker B taken 10 hours to the same job how long should it take both A and B, working together what independently to do in the same job ?

A’s 1 hours work =1/8

B’s 1 hours work =1/10

(A plus B)’s 1 hours work = ( 1/8 plus 1/10)

= 9/40

4 4/9 days

#18. A can do a certain job in 12 days , B is 60 % more efficient then A how many days does B alone taken to do same job?

A can do a certain job in 12 days , B is 60 % more efficient then A how many days does B alone taken to do same job?

Ratio of time taken by A and B = 160 : 100

= 8 : 5

suppose B alone takes X days  to do the job

8 : 5 :: 12 : X

8 x = 5* 12

x= 7 1/2 days

#19. A job can be done by 3 skilled workmen in 20 days or by 5 boys in 30 days . How many days will they take if they work together?

A job can be done by 3 skilled workmen in 20 days or by 5 boys in 30 days . How many days will they take if they work together?

job of 3 skilled men in 20 days = job of 5 boys in 30 days

time = 20 * 30/ 20 plus 30

= 12 days

Finish

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