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Jan 24, 2011 11:40 am
Kudos
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B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
76% (01:29) correct
24%
(01:48)
wrong
based on 62
sessions
History
Date
Time
Result
Not Attempted Yet
If rs ≠ 0, is \(\frac{1}{r}+ \frac{1}{s} = 6\)?
(1) \(r = 3s\)
(2) \(rs= \frac{(r+s)}{6}\)
(1) \(r = 3s\)
(2) \(rs= \frac{(r+s)}{6}\)
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
Jan 24, 2011 12:31 pm
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gmatpapa
(1) \(r = 3s\) implies \(\frac{r}{s} = 3\), which is not enough to find the value of \(\frac{1}{r}+ \frac{1}{s}\)
So, statement 1 is NOT SUFFICIENT.
(2) \(rs= \frac{(r+s)}{6}\) implies \(6 = \frac{(r + s)}{rs}\)
\(6 = \frac{r}{rs} + \frac{s}{rs}\)
\(6 = \frac{1}{s} + \frac{1}{r}\)
So, answer to the main question is "yes".
Hence statement 2 is SUFFICIENT.
The correct answer is B.
Jan 24, 2011 1:21 pm
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gmatpapa
Is \(\frac{1}{r}+ \frac{1}{s} = 6\)? --> is \(\frac{r+s}{rs}=6\)?
(1) \(r = 3s\) --> question becomes: is \(\frac{3s+s}{3s^2}=6\) --> is \(s=\frac{2}{9}\)? We don't know that. Not sufficient.
(2) \(rs= \frac{(r+s)}{6}\) --> we can rewrite it as: \(\frac{r+s}{rs}=6\) --> directly gives the answers YES. Sufficient.
Answer: B.
