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B
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Difficulty:
15%
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Question Stats:
75% (00:56) correct
25%
(01:20)
wrong
based on 114
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If x ≠ y, what is the value of x + y?
(1) x - y = 1
(2) x^2- y^2 = x - y
(1) x - y = 1
(2) x^2- y^2 = x - y
Correct Answer is "B - Statement (2) ALONE is sufficient, but statement (1) is NOT sufficient"
But I believe it should be "D - EACH statement ALONE is sufficient". Why because:
Consider (2)
\(X2- y 2 = x - y\) => \((x+y)(x-y) = (x-y)\) => \(x+y = 1\) by cancelling \(x-y\) on both sides Sufficient
Now, consider (1) \(x - y = 1\).
Adding \(2y\) on both sides,
\(x+y = 1 + 2y.\)
I agree, this does not give a concrete answer like case 2 (which gave x+y = 1). But this expression "\(x+y = 1 + 2y\)" will help me find the answer for x+y provided I know the value of y. Isn't it?
The guide says,
Thus, I say I can find the value of x+y either with 1st 2nd statement alone (i.e., EACH statement ALONE is sufficient).
I am not saying I am correct. I know I am wrong because my answer is not matching with the correct answer. Its just that I do not seem to understand. Can someone correct me, please?
But I believe it should be "D - EACH statement ALONE is sufficient". Why because:
Consider (2)
\(X2- y 2 = x - y\) => \((x+y)(x-y) = (x-y)\) => \(x+y = 1\) by cancelling \(x-y\) on both sides Sufficient
Now, consider (1) \(x - y = 1\).
Adding \(2y\) on both sides,
\(x+y = 1 + 2y.\)
I agree, this does not give a concrete answer like case 2 (which gave x+y = 1). But this expression "\(x+y = 1 + 2y\)" will help me find the answer for x+y provided I know the value of y. Isn't it?
The guide says,
Quote:
Thus, I say I can find the value of x+y either with 1st 2nd statement alone (i.e., EACH statement ALONE is sufficient).
I am not saying I am correct. I know I am wrong because my answer is not matching with the correct answer. Its just that I do not seem to understand. Can someone correct me, please?
13 Dec 2013, 06:57
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flower07
If x ≠ y, what is the value of x + y?
(1) x - y = 1. If x=1 and y=0, then x+y=1 but if x=2 and y=1, then x+y=3. We have two different answers thus the statement is not sufficient.
(2) x^2- y^2 = x - y --> (x-y)(x+y)=x-y. Now, since we are given that x-y≠0, then we can safely reduce by it and we get: x+y=1. Sufficient.
Answer: B.
As for your doubt. There are two kinds of data sufficient questions: YES/NO DS questions and DS questions which ask to find a value.
In a Yes/No Data Sufficiency questions, statement is sufficient if the answer is “always yes” or “always no” while a statement is insufficient if the answer is "sometimes yes" and "sometimes no".
When a DS question asks about the value of some variable, then the statement is sufficient ONLY if you can get the single numerical value of this variable.
Now, our original question is asking about the value of x+y, thus the statement is sufficient ONLY if you can get the single numerical value of this expression.
Hope it's clear.
P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to the rules 2, 3, and 10. Thank you.
28 Jun 2024, 15:02
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