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A, B and C can complete a piece of work in 24 days, 40 days and 60 day

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A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 00:42
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  35% (medium)

Question Stats:

67% (01:13) correct 33% (01:11) wrong based on 148 sessions

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A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.

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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 01:53
1
Bunuel wrote:
A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.


A does 1/24 of work in 1 day
B does 1/40 of work in 1 day
C does 1/60 of work in 1 day

(1) gives us A+B+C started together and A continued till the end but we do not know for how many days B & C worked
Not sufficient

(2) A+B+C started together, B worked for 2 days and C worked for 7 Days

We can say that

For 2 days (A+B+C)
For 5 days (A+C)
For the rest of days A alone

Lets assume the work to be 240 units
A works for 10 units/day
B works for 6 units/day
C works for 4 units/day

A+B+C = 20 units/day
A+C = 14 units/day

But we don't know if A continued till the end (Cannot assume that A completed the work after 7 days) hence Not sufficient
On combining both we can form the equation

2*20 + 5*14 + x*10 = 240

We can find x and add 7 days to it to get the answer

Hence C
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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 02:12
2
Bunuel wrote:
A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.


(1) B and C could work any number of days, so not sufficient
(2) A worked (t+9) days

(t+9)x(1/24)+2/40+7/60=1;
(t+9)/24=120/120-6/120-14/120;
(t+9)/24=100/120;
t+9= 5/6x24 = 20 => a piece of work was completed in 20 days.

B
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A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 02:19
Akela wrote:
Bunuel wrote:
A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.


(1) B and C could work any number of days, so not sufficient
(2) A worked (t+9) days

(t+9)x(1/24)+2/40+7/60=1;
(t+9)/24=120/120-6/120-14/120;
(t+9)/24=100/120;
t+9= 5/6x24 = 20 => a piece of work was completed in 20 days.

B

Akela Although t+9 or t+7 wont matter but i think it should be t+7 (if u are assuming t days when A worked alone). please correct me if i am wrong
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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 05:52
1
mynamegoeson wrote:
Akela wrote:
Bunuel wrote:
A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.


(1) B and C could work any number of days, so not sufficient
(2) A worked (t+9) days

(t+9)x(1/24)+2/40+7/60=1;
(t+9)/24=120/120-6/120-14/120;
(t+9)/24=100/120;
t+9= 5/6x24 = 20 => a piece of work was completed in 20 days.

B

Akela Although t+9 or t+7 wont matter but i think it should be t+7 (if u are assuming t days when A worked alone). please correct me if i am wrong


You're right, I misread statement 2. A worked t days, b worked (t-2) days, and c worked (t-7) days: t/24+(t-2)/40+(t-7)/60=1
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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 05 Jul 2017, 08:41
Hi ,
This Ds question we do not need to solve completely. Let us start with info in hand. We know by given data that
A's one day work =1/24
B's one day work =1/40
C's one day work =1/60
Q: In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
As there is no info when B and C left the work so we can not say in how many days work was completed. Insufficient
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.
Start with info 2: here we know how many days B and c Worked and rest is done by A. Hence this is sufficient .

for those who want to solve: lets say in total t days work was completed.

A's t day work =t/24
B's 2 day work= 2/40
C's 7 day work =7/60

t/24 + 2/40 +7/60 =1 solve this equation to find value of t.

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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 19 Jul 2017, 01:21
mbaaspirant80 wrote:
Hi ,
This Ds question we do not need to solve completely. Let us start with info in hand. We know by given data that
A's one day work =1/24
B's one day work =1/40
C's one day work =1/60
Q: In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
As there is no info when B and C left the work so we can not say in how many days work was completed. Insufficient
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.
Start with info 2: here we know how many days B and c Worked and rest is done by A. Hence this is sufficient .

for those who want to solve: lets say in total t days work was completed.

A's t day work =t/24
B's 2 day work= 2/40
C's 7 day work =7/60

t/24 + 2/40 +7/60 =1 solve this equation to find value of t.

Thanks



Can u please tell me if my approach is correct or not and if I am solving it right or not?

A's one day work =1/24
B's one day work =1/40
C's one day work =1/60

Working together for first 2 days = (1/24 + 1/40+ 1/60) *2
A and C Working together for next 5 days = (1/24 + 1/60) *5
A working alone for rest of the days = (1/24)*x

(1/24 + 1/40+ 1/60) *2 + (1/24 + 1/60) *5 + (1/24)*x = 1

AND WE CAN FIND x by this?


Please tell me if i solved it right or wrong:?
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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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New post 19 Jul 2017, 01:23
Bunuel wrote:
A, B and C can complete a piece of work in 24 days, 40 days and 60 days, respectively. In how many days was the piece of work completed?

(1) A, B and C started working together, and A continued to work till the end.
(2) A, B and C started working together, B and C left the work 2 days and 7 days, respectively, before the completion of the work.




Can u please tell me if my approach is correct or not and if I am solving it right or not?

A's one day work =1/24
B's one day work =1/40
C's one day work =1/60

Working together for first 2 days = (1/24 + 1/40+ 1/60) *2
A and C Working together for next 5 days = (1/24 + 1/60) *5
A working alone for rest of the days = (1/24)*x

(1/24 + 1/40+ 1/60) *2 + (1/24 + 1/60) *5 + (1/24)*x = 1

AND WE CAN FIND x by this?


Please tell me if i solved it right or wrong:?
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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day  [#permalink]

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Re: A, B and C can complete a piece of work in 24 days, 40 days and 60 day &nbs [#permalink] 20 Sep 2018, 14:03
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