Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 21 Jul 2009
Posts: 140
Location: New York, NY

If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
Updated on: 17 Sep 2009, 09:06
Question Stats:
64% (01:32) correct 36% (01:38) wrong based on 942 sessions
HideShow timer Statistics
If w women can do a job in d days, then how many days will it take (w + n) women to do the job if all the women work at the same pace? A. \(\frac{dw}{n+w}\) B. \(\frac{n+w}{d}\) C. \(\frac{n+w}{dw}\) D. \(\frac{d}{n+w}\) E. \(\frac{d(n+w)}{w}\)
Official Answer and Stats are available only to registered users. Register/ Login.
Originally posted by mendelay on 10 Sep 2009, 07:18.
Last edited by mendelay on 17 Sep 2009, 09:06, edited 1 time in total.




GMAT Tutor
Joined: 24 Jun 2008
Posts: 1829

Re: Working women
[#permalink]
Show Tags
10 Sep 2009, 07:47
I'd do this as maliyeci did above, but just wanted to point out an alternative strategy: if n=0, clearly the answer must be d. That gets down to A or E; if more women work on the task, the time required will fall, so n+d needs to be in the denominator. That gets us to A. And of course one could plug in numbers, though that might be the most timeconsuming approach.
_________________
GMAT Tutor in Toronto
If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com




Senior Manager
Joined: 23 Jun 2009
Posts: 283
Location: Turkey
Schools: UPenn, UMich, HKS, UCB, Chicago

Re: Working women
[#permalink]
Show Tags
10 Sep 2009, 07:23
a women can do 1/wd part of the job in one day so that w woman can do all of the job in d days.
That makes (w+n) women can do (w+n)/wd part of the job in 1 day.
Day can do all of the job in 1/((w+n)/wd)=wd/(w+n)
A



Intern
Joined: 09 Aug 2009
Posts: 33

Re: Working women
[#permalink]
Show Tags
14 Sep 2009, 03:35
we know number of women and days are inversely prop . according to rule (number of women*days) =( number of women + number of extra women) * days here to keep the work same if number of women increases days has to decreases. so new days = wd/(w+n)
/Prabu



Manager
Joined: 22 Mar 2009
Posts: 56
Schools: Darden:Tepper:UCUIC:Kenan Flager:Nanyang:NUS:ISB:UCI Merage:Emory
WE 1: 3

Re: Working women
[#permalink]
Show Tags
14 Sep 2009, 05:39
as mentioned in the question ...work rate should be equal in both cases so:
w*d = (w+n)*X X = no of days with (w+n) workers = {wd/w+n}



Intern
Joined: 28 May 2013
Posts: 3

Re: Working women
[#permalink]
Show Tags
28 Jun 2013, 21:42
w women can finish in d days. w+n women can finish work in x days
w d w+nx x= (w+n)d/w
E is the answer



Math Expert
Joined: 02 Sep 2009
Posts: 59587

Re: Working women
[#permalink]
Show Tags
28 Jun 2013, 22:24
bopi wrote: w women can finish in d days. w+n women can finish work in x days
w d w+nx x= (w+n)d/w
E is the answer Please note that the correct answer is A, not E. If w women can do a job in d days, then how many days will it take (w + n) women to do the job if all the women work at the same pace?A. \(\frac{dw}{n+w}\) B. \(\frac{n+w}{d}\) C. \(\frac{n+w}{dw}\) D. \(\frac{d}{n+w}\) E. \(\frac{d(n+w)}{w}\) The job consists of \(wd\) units of work (1 woman does 1 unit of work in 1 day). Thus \(w + n\) women will take \(\frac{wd}{w+n}\) days to do the job. Answer: A. Hope it's clear.
_________________



Intern
Joined: 04 May 2013
Posts: 39

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
30 Jul 2013, 15:16
Can you please explain why the answer is not E.
I understand that this is an inversely proportion problem. So it wont be just (w+n)*d/w
For example, if 10 women can do the job in 10 days, how many days will 20 women take to finish the job? The answer will be 5, not 20.
So I understand this particular concept, but I want to recognize that this is an inverse proportion problem without plugging in the number everytime, because I am trying to do it quicker.
Is there a way to recognize this? Other that just practice?
Thanks



Manager
Status: Persevering
Joined: 15 May 2013
Posts: 146
Location: India
Concentration: Technology, Leadership
GMAT Date: 08022013
GPA: 3.7
WE: Consulting (Consulting)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
31 Jul 2013, 05:01
jjack0310 wrote: Can you please explain why the answer is not E.
I understand that this is an inversely proportion problem. So it wont be just (w+n)*d/w
For example, if 10 women can do the job in 10 days, how many days will 20 women take to finish the job? The answer will be 5, not 20.
So I understand this particular concept, but I want to recognize that this is an inverse proportion problem without plugging in the number everytime, because I am trying to do it quicker.
Is there a way to recognize this? Other that just practice?
Thanks Now try to understand this w women take d days 1 women will take d*w days w+n will then take d*w/w+n Regards, Ramandeep
_________________
It's one thing to get defeated, but another to accept it.



Intern
Joined: 07 Jan 2013
Posts: 18
Location: Poland
GPA: 3.8

Re: Working women
[#permalink]
Show Tags
11 Oct 2013, 21:19
Bunuel wrote: bopi wrote: w women can finish in d days. w+n women can finish work in x days
w d w+nx x= (w+n)d/w
E is the answer Please note that the correct answer is A, not E. If w women can do a job in d days, then how many days will it take (w + n) women to do the job if all the women work at the same pace?A. \(\frac{dw}{n+w}\) B. \(\frac{n+w}{d}\) C. \(\frac{n+w}{dw}\) D. \(\frac{d}{n+w}\) E. \(\frac{d(n+w)}{w}\) The job consists of \(wd\) units of work (1 woman does 1 unit of work in 1 day). Thus \(w + n\) women will take \(\frac{wd}{w+n}\) days to do the job. Answer: A. Hope it's clear. Banuel, could you pls explain how did you proceed but step by step maybe with some example? Magda



Intern
Joined: 16 Dec 2011
Posts: 1

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
11 Oct 2013, 22:31
Let us consider work done as 1 unit. if w women takes d days to complete the work. then in one day they will complete 1/d work. and 1 women can complete 1/wd of work in a day. now we have total of n+w women now.
work done for one day by n+w women=work done for one day by one women*no of women =1/wd *(n+w) =(n+w)/wd time taken to complete the work =wd/n+w



Intern
Joined: 19 Jul 2012
Posts: 19
Location: United States
Concentration: Operations, Entrepreneurship
WE: Consulting (Manufacturing)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
15 Oct 2013, 11:22
Point to remember: General formula for equating work of two groups:
(M1 D1 H1)/W1 E1 = (M2 D2 H2)/W2 E2
Where M  Number of people D  Number of days H  Number of hours E  Efficiency W  Work done In the above problem w women take d days: So let w+n women take X days?
i.e w * d = (w+n) * X or X = wd/(w+n) days Hence Option A



Intern
Joined: 15 Dec 2007
Posts: 12

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
16 Oct 2013, 00:00
Number picking is another way to solve this. Lets decide, that we have 5(w) women in the beggining, and 20(n) were added at the end. So w+n=25. Lets say that 5 women can do a certain job in 50 days. Than 25 women can do same job in 50/5=10 days. Test answers to get answer = 10 days. It is A.



Retired Moderator
Joined: 20 Dec 2013
Posts: 166
Location: United States (NY)
GMAT 1: 640 Q44 V34 GMAT 2: 710 Q48 V40 GMAT 3: 720 Q49 V40
GPA: 3.16
WE: Consulting (Venture Capital)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
16 Jan 2014, 21:21
here's how I worked it out woman rate = x; so one woman can do one job in 1/x days (inverse) W women rate = w/x; we are told W women can do the job in d days so x/w = d W+n women rate = (w+n)/x; x/(w+n) = z days solve for z x/w = d > x = wd wd/(w+n) = z days
_________________



Manager
Joined: 26 May 2013
Posts: 91

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
06 Feb 2014, 13:13
This is a great problem to plug numbers into:
Say 10 women complete a job in 20 days
w = 10 , d = 20
Then add another 10 n women and your days will be cut in half to 10 days (you doubled the women working on the job)
Conveniently the first answer choice gives you the answer
20(10) / 10+10 = 10



Intern
Joined: 05 Mar 2014
Posts: 9

If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
29 Mar 2014, 11:06
Answer is A.
Ive done an analogy to facilitate.
W (women = speed) D (days = time)
W*D = X (distance)
we want time (D) if there are more speed (more n women)
So, in analogy we have Distance/Time = Speed, Time = Distance/Speed
We know that our distance didn`t change, it`s X, or W*D.
Our speed by the way changed from W to W + N.
So substituting we have: W*D(Distance)/(W + N)(Speed) = Time
Answer A



Manager
Joined: 08 Sep 2010
Posts: 56

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
23 Apr 2014, 08:26
My approach is similar to bunuel.
w women work for d days. Total work hours = w*d
Now w+n women will take w*d/(w+n) days to complete the w*d work hours. Hence option A.



Board of Directors
Joined: 17 Jul 2014
Posts: 2492
Location: United States (IL)
Concentration: Finance, Economics
GPA: 3.92
WE: General Management (Transportation)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
01 Feb 2016, 19:22
to be honest..I hate problems with VIC's... we have w women and d days to complete the task the rate is thus 1/d the rate of each woman is 1/d : w or 1/dw now, we have w+n women the rate of all of them will be (w+n)/dw
now, how long will these women take to finish the job? 1: (w+n)/dw or dw/(w+n)



CEO
Joined: 20 Mar 2014
Posts: 2561
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
01 Feb 2016, 19:30
mvictor wrote: to be honest..I hate problems with VIC's... we have w women and d days to complete the task the rate is thus 1/d the rate of each woman is 1/d : w or 1/dw now, we have w+n women the rate of all of them will be (w+n)/dw
now, how long will these women take to finish the job? 1: (w+n)/dw or dw/(w+n) Why dont you make your life easy and plug in values for the variables. Then use the same pluggd in valued to analyse which of the options give you the same value. Try w=10, d=5, n=15, n+w=25, giving you the number of days for 25 women = 2 days. Analyse the options: A: = 2 . KeepB: = 5. Eliminate.C: = 0.5 .Eliminate.D: = 0.2. Eliminate.E: = 12.5. Eliminate.Thus only A is left and is hence the correct answer. You should use this approach when you are given a question full of variables and the answer choices are also in terms of those variables.



Board of Directors
Joined: 17 Jul 2014
Posts: 2492
Location: United States (IL)
Concentration: Finance, Economics
GPA: 3.92
WE: General Management (Transportation)

Re: If w women can do a job in d days, then how many days will
[#permalink]
Show Tags
02 Feb 2016, 09:43
Engr2012 wrote: mvictor wrote: to be honest..I hate problems with VIC's... we have w women and d days to complete the task the rate is thus 1/d the rate of each woman is 1/d : w or 1/dw now, we have w+n women the rate of all of them will be (w+n)/dw
now, how long will these women take to finish the job? 1: (w+n)/dw or dw/(w+n) Why dont you make your life easy and plug in values for the variables. Then use the same pluggd in valued to analyse which of the options give you the same value. Try w=10, d=5, n=15, n+w=25, giving you the number of days for 25 women = 2 days. Analyse the options: A: = 2 . KeepB: = 5. Eliminate.C: = 0.5 .Eliminate.D: = 0.2. Eliminate.E: = 12.5. Eliminate.Thus only A is left and is hence the correct answer. You should use this approach when you are given a question full of variables and the answer choices are also in terms of those variables. i tried to plug in values for 1 woman, and for days to complete 2. but then it got messy, and I just simply decided to go with the algebraic approach.




Re: If w women can do a job in d days, then how many days will
[#permalink]
02 Feb 2016, 09:43



Go to page
1 2
Next
[ 28 posts ]



