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reddevil00
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06 Apr 2012, 18:49
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D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
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If (x/y)^(1/2)=n, what is the value of x?
(1) (n^2)y = 100
(2) n= 5 and y = 4
(1) (n^2)y = 100
(2) n= 5 and y = 4
This question is from Total GMAT Math. The statement (1) provides that (n^2)y = 100 which implies that n(y^(1/2)) can be either 10 or -10. However, the solution provided by the book states that the above value is only 10. Hence I chose B, sine the statement (1) can be both 10 or -10. Is my approach incorrect?
The official answer is D.
Thanks in advance for your expertise!
The official answer is D.
Thanks in advance for your expertise!
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
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Thank you for understanding, and happy exploring!
06 Apr 2012, 21:09
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Rearranging/squaring the equation given in the question saves you from the troubles with square roots.
\(\sqrt{\frac{x}{y}}=n\)
\(\frac{x}{y}=n^2\)
\(x=(n^2)y\)
Statement 1: \((n^2)y=100\)
Hence statement 1 is sufficient.
Also if you were to continue from the equation you've arrived at,
When its 10:
\(n\sqrt{y}=10\)
\((n^2)y=10^2\)
\((n^2)y=100=x\)
When its -10:
\(n\sqrt{y}=-10\)
\((n^2)y=(-10)^2\)
\((n^2)y=100=x\)
Both lead to \(x=100\) so statement 1 is still sufficient.
\(\sqrt{\frac{x}{y}}=n\)
\(\frac{x}{y}=n^2\)
\(x=(n^2)y\)
Statement 1: \((n^2)y=100\)
Hence statement 1 is sufficient.
Also if you were to continue from the equation you've arrived at,
When its 10:
\(n\sqrt{y}=10\)
\((n^2)y=10^2\)
\((n^2)y=100=x\)
When its -10:
\(n\sqrt{y}=-10\)
\((n^2)y=(-10)^2\)
\((n^2)y=100=x\)
Both lead to \(x=100\) so statement 1 is still sufficient.
harshavmrg
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07 Apr 2012, 02:06
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andrewh
1) (n^2)y = 100
2) n= 5 and y = 4
This question is from Total GMAT Math. The statement (1) provides that (n^2)y = 100 which implies that n(y^(1/2)) can be either 10 or -10. However, the solution provided by the book states that the above value is only 10. Hence I chose B, sine the statement (1) can be both 10 or -10. Is my approach incorrect?
The official answer is D.
Thanks in advance for your expertise!
2) n= 5 and y = 4
This question is from Total GMAT Math. The statement (1) provides that (n^2)y = 100 which implies that n(y^(1/2)) can be either 10 or -10. However, the solution provided by the book states that the above value is only 10. Hence I chose B, sine the statement (1) can be both 10 or -10. Is my approach incorrect?
The official answer is D.
Thanks in advance for your expertise!
Given that
(x/y)power(1/2) = n
x/y = n square
x = y. n square
now,
1. y.nsquare = 100
sufficient
2. values for Y and N are given, then this is sufficient too...
so my ANSWER is D
.
