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# If w women can do a job in d days, then how many days will

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

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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 . Keep
B: = 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.
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Re: If w women can do a job in d days, then how many days will  [#permalink]

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30 Jan 2017, 04:51
1) First of all we need to set up an equation for w women and find the rate for each woman: $$w*r*d=1; r=\frac{1}{wd}$$
2) Now let's set up an equation for (w+n) women: $$(w+n)*\frac{1}{wd}*T=1; T=\frac{1}{(w+n)/wd}=\frac{wd}{w+n}$$
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Re: If w women can do a job in d days, then how many days will  [#permalink]

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02 Apr 2017, 11:46
M1D1=M2D2
w*d=(w+n)*D2
D2=wd/(w+n)

M=no of women
D= no of days

Posted from my mobile device
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If w women can do a job in d days, then how many days will  [#permalink]

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02 Apr 2017, 12:14
mendelay wrote:
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. $$\frac{d(n+w)}{w}$$

rate of 1 woman=1/dw
rate of n+w women=n+w/dw
inverting, time for n+w women=dw/n+w days
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Re: If w women can do a job in d days, then how many days will  [#permalink]

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06 Jun 2017, 16:09
mendelay wrote:
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. $$\frac{d(n+w)}{w}$$

1. 1 woman can do the job is dw days
2. w+n women can do the job is dw/(w+n) days
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Re: If w women can do a job in d days, then how many days will  [#permalink]

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08 Oct 2018, 02:44
Could someone explain the flaw in this approach please:

RateWomen x Time = Work Done

Rw X d = 1
Rw = 1/d

(w+n)*1/d x T = 1
(w+n)/d x T = 1
T = d/w+n

I am getting Ans. D

:/
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Re: If w women can do a job in d days, then how many days will  [#permalink]

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08 Oct 2018, 03:32
PierTotti17 wrote:
Could someone explain the flaw in this approach please:

RateWomen x Time = Work Done

Rw X d = 1
Rw = 1/d

(w+n)*1/d x T = 1
(w+n)/d x T = 1
T = d/w+n

I am getting Ans. D

:/

w women take d days to complete 1 work. What is Rw here? Rate of work of 1 woman or w women?
Or is it R*w (R the rate of each woman and w the number of women?)
If that were the case, R = 1/dw (Rate of each woman)

(w + n)*(1/dw) * Time = 1

Time = dw/(w + n)

Alternatively, one could plug in numbers:

I say, n = 0. So the work will be done by w+n women in d days. Plugging n = 0 in options, only (A) and (E) give us d.

Next, say 1 woman completes the work in 1 day. 2 women (n = 1) will do it in 1/2 day. Plugging in options (A) and (E), only option (A) gives 1/2

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

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08 Oct 2018, 09:36
PierTotti17 wrote:
Could someone explain the flaw in this approach please:

RateWomen x Time = Work Done

Rw X d = 1
Rw = 1/d

(w+n)*1/d x T = 1
(w+n)/d x T = 1
T = d/w+n

I am getting Ans. D

:/

w women take d days to complete 1 work. What is Rw here? Rate of work of 1 woman or w women?
Or is it R*w (R the rate of each woman and w the number of women?)
If that were the case, R = 1/dw (Rate of each woman)

(w + n)*(1/dw) * Time = 1

Time = dw/(w + n)

Alternatively, one could plug in numbers:

I say, n = 0. So the work will be done by w+n women in d days. Plugging n = 0 in options, only (A) and (E) give us d.

Next, say 1 woman completes the work in 1 day. 2 women (n = 1) will do it in 1/2 day. Plugging in options (A) and (E), only option (A) gives 1/2

w women take d days to complete 1 work. What is Rw here? Rate of work of 1 woman or w women?
Or is it R*w (R the rate of each woman and w the number of women?)
If that were the case, R = 1/dw (Rate of each woman)

In my mind, I am doing: Rate of Women x Time = Work

I guess my mistake is that I need to take into consideration the INDIVIDUAL work done by each woman. It's just confusing in my head because the question stem says: "if w women do a job in d days.." doesn't that imply that the Rate is of the collective women? Not sure why we have to take each individual one.

But thank you for the reply! This is something I would 100% get wrong on the test due to some confusing wording.
Re: If w women can do a job in d days, then how many days will   [#permalink] 08 Oct 2018, 09:36

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