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05 May 2017, 06:49
Kudos
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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)!
Difficulty:
45%
(medium)
Question Stats:
61% (01:46) correct
39%
(01:41)
wrong
based on 72
sessions
History
Date
Time
Result
Not Attempted Yet
If \(xy = - 9\), what is the value of \(xy(x+y)\)?
(1) \(x - y = 6\)
(2) \(xy^{2} = 27\)
Source: Self-made
(1) \(x - y = 6\)
(2) \(xy^{2} = 27\)
Source: Self-made
05 May 2017, 07:16
Kudos
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ganand
IMO, (D) is the answer, i.e. each statement is sufficient to answer this.
Using Statement (1) alone,
\(x - y = 6\), and xy=-9
Using both these equations, y = -3 and x = 3.
Therefore, \(xy(x+y)\)
= -9(-3+3) = 0
Using statement (2) alone,
\(xy^{2} = 27\) and xy=-9
Using both these equations, -9y = 27, so y =-3. Hence x = 3
Therefore, \(xy(x+y)\)
= -9(-3+3) = 0
Thus, each statement alone is sufficient to answer this.
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05 May 2017, 21:15
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ganand
As per the question stem you simply need the value of (x+y) or values of both x & y
Statement 1: we can directly get x+y using the formula: (x+Y)^2 = (x-y)^2 + 4xy
solving this we will get x+y = 0. Hence sufficient
Statement 2: can be simplified as xy(y) = 27
substituting the value of xy and solving we get y=-3 and x=3. Hence sufficient
So, option D
