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Working together, Rafael and Salvador can tabulate a certain set of da

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Working together, Rafael and Salvador can tabulate a certain set of da  [#permalink]

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03 Aug 2018, 09:35
00:00

Difficulty:

25% (medium)

Question Stats:

69% (01:30) correct 31% (02:10) wrong based on 277 sessions

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Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.

NEW question from GMAT® Quantitative Review 2019

(DS13907)

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Re: Working together, Rafael and Salvador can tabulate a certain set of da  [#permalink]

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03 Aug 2018, 12:39
2
1
Bunuel wrote:
Working together, Rafael and Salvador can tabulate a certain set of data in 2 hours. In how many hours can Rafael tabulate the data working alone?

(1) Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
(2) Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.

NEW question from GMAT® Quantitative Review 2019

(DS13907)

Let 'r' and 's' are the no of hours taken by Rafael & Salvador, working alone, to complete the job respectively.

Given, $$\frac{1}{r}+\frac{1}{s}=\frac{1}{2}$$-------------(1)

Question stem:- r=?

St1:- Working alone, Rafael can tabulate the data in 3 hours less time than Salvador, working alone, can tabulate the data.
Or, r=s-3 Or, s=r+3
from(1), we have, $$\frac{1}{r}+\frac{1}{s}=\frac{1}{2}$$
Now substituting, $$\frac{1}{r}+\frac{1}{(r+3)}=\frac{1}{2}$$
Or, $$r^2-r-6=0$$
Or, (r+2)(r-3)=0
Or, r=3
Sufficient.

St2:- Working alone, Rafael can tabulate the data in 1/2 the time that Salvador, working alone, can tabulate the data.
Or, $$r=\frac{s}{2}$$ Or, $$s=2r$$
from(1), we have, $$\frac{1}{r}+\frac{1}{s}=\frac{1}{2}$$
Now substituting, $$\frac{1}{r}+\frac{1}{2r}=\frac{1}{2}$$
Or, 2r=6
Or, r=3
Sufficient.

Ans. (D)
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Re: Working together, Rafael and Salvador can tabulate a certain set of da &nbs [#permalink] 03 Aug 2018, 12:39
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