GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 23 Oct 2019, 16:58

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# M and N working together, can finish a job in 6 days

Author Message
TAGS:

### Hide Tags

e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3092
M and N working together, can finish a job in 6 days  [#permalink]

### Show Tags

Updated on: 27 Aug 2018, 03:09
00:00

Difficulty:

15% (low)

Question Stats:

85% (02:15) correct 15% (02:45) wrong based on 94 sessions

### HideShow timer Statistics

M and N working together, can finish a job in 6 days. With the help of P, they completed the job in 4 days. If Q joined them, all 4 together would have completed the job in 3$$\frac{1}{3}$$ days. If all work at their respective constant rate, then in how many days Q alone can complete the work?

A. 10
B. 12
C. 15
D. 18
E. 20

_________________

Originally posted by EgmatQuantExpert on 27 Aug 2018, 02:51.
Last edited by EgmatQuantExpert on 27 Aug 2018, 03:09, edited 1 time in total.
Math Expert
Joined: 02 Aug 2009
Posts: 8023
M and N working together, can finish a job in 6 days  [#permalink]

### Show Tags

27 Aug 2018, 02:59
1
1
EgmatQuantExpert wrote:
M and N working together, can finish a job in 6 days. With the help of P, they completed the job in 4 days. If Q joined them, all 4 together would have completed the job in 31/3 days. If all work at their respective constant rate, then in how many days Q alone can complete the work?

A. 10
B. 12
C. 15
D. 18
E. 20

All four can complete the job in 3 and 1/3 days or 10/3 , so 1 day work =3/10
All except Q can complete job in 4 days, so their 1 day work=1/4

So 1 day work of Q = 3/10-1/4=(12-10)/40=1/20
So total work in 20 days..

E

EgmatQuantExpert, how can 3 people finish faster in 4 days as compared to a situation when a fourth person joins them and now in 31/3=10 days ?????
_________________
e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3092
Re: M and N working together, can finish a job in 6 days  [#permalink]

### Show Tags

27 Aug 2018, 03:13
chetan2u wrote:

All four can complete the job in 31/3 days , so 1 day work =3/31
All except Q can complete job in 4 days, so their 1 day work=1/4

EgmatQuantExpert, how can 3 people finish faster in 4 days as compared to a situation when a fourth person joins them and now in 31/3=10 days ?????

It was a tagging error. It should be 3$$\frac{1}{3}$$ days not 31/3.
We have corrected it.
_________________
VP
Joined: 09 Mar 2016
Posts: 1230
Re: M and N working together, can finish a job in 6 days  [#permalink]

### Show Tags

27 Aug 2018, 07:12
1
chetan2u wrote:
EgmatQuantExpert wrote:
M and N working together, can finish a job in 6 days. With the help of P, they completed the job in 4 days. If Q joined them, all 4 together would have completed the job in 31/3 days. If all work at their respective constant rate, then in how many days Q alone can complete the work?

A. 10
B. 12
C. 15
D. 18
E. 20

All four can complete the job in 3 and 1/3 days or 10/3 , so 1 day work =3/10All except Q can complete job in 4 days, so their 1 day work=1/4

So 1 day work of Q = 3/10-1/4=(12-10)/40=1/20
So total work in 20 days..

E

EgmatQuantExpert, how can 3 people finish faster in 4 days as compared to a situation when a fourth person joins them and now in 31/3=10 days ?????

what is the reason you switched 10/3 to 3/10 ?
Math Expert
Joined: 02 Aug 2009
Posts: 8023
Re: M and N working together, can finish a job in 6 days  [#permalink]

### Show Tags

27 Aug 2018, 07:23
1
dave13 wrote:
chetan2u wrote:
EgmatQuantExpert wrote:
M and N working together, can finish a job in 6 days. With the help of P, they completed the job in 4 days. If Q joined them, all 4 together would have completed the job in 31/3 days. If all work at their respective constant rate, then in how many days Q alone can complete the work?

A. 10
B. 12
C. 15
D. 18
E. 20

All four can complete the job in 3 and 1/3 days or 10/3 , so 1 day work =3/10All except Q can complete job in 4 days, so their 1 day work=1/4

So 1 day work of Q = 3/10-1/4=(12-10)/40=1/20
So total work in 20 days..

E

EgmatQuantExpert, how can 3 people finish faster in 4 days as compared to a situation when a fourth person joins them and now in 31/3=10 days ?????

what is the reason you switched 10/3 to 3/10 ?

dave13
If someone can do a job in 10 days so each day he does 1/10 th of work..
So here also they complete the work in 10/3 days, thus in one day they can do 3/10th of work as 1/(10/3)=1*3/10=3/10

If A is doing 1/2 of the work in one day, A will complete full work in 2 days as 1/(1/2)=1*2/1=2
_________________
Re: M and N working together, can finish a job in 6 days   [#permalink] 27 Aug 2018, 07:23
Display posts from previous: Sort by