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12 Jun 2023, 06:15
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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:
95%
(hard)
Question Stats:
39% (02:28) correct
61%
(02:35)
wrong
based on 161
sessions
History
Date
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Not Attempted Yet
If \(|a+1|=|b-1|\), what is the value of \(a-b\) ?
(1) \(ab>0\)
(2) \(\frac{a}{b}≠ -1\)
(1) \(ab>0\)
(2) \(\frac{a}{b}≠ -1\)
14 Jun 2023, 23:05
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Bunuel
\(|a+1|=|b-1|\)
This eqn only holds for certain combinations of \(a\) and \(b\)
i.e. if \(a=4\) then \(b\) has to be either \(6\) or \(-4\)
So \(a-b\) can be either \(-2\) or \(8\)
If \(a=-6\) then \(b\) can be \(6\) or \(-4\)
So \(a-b=-12\) or \(-2\)
Similarly we can verify by taking other numbers too
(1) \(ab>0\)
This implies \(a\) and \(b\) have to have the same sign
So if \(a\) is \(4 \) then \(b\) has to be \(6\) and \(a-b=-2 \)
If \(a=-6\) then \(b\) has to be \(-4\) and \(a-b=-2\)
(other values for a and b will give similar result)
SUFF.
(2) \(\frac{a}{b}≠ -1\)
Again from our pre-work we can see that we cannot have \(a=4\) and \(b=-4\) nor can we have \(a=-6\) and \(b=6\)
Thus the only other possibility is \(a=4\) and \(b=6\) or \(a=-6\) and \(b=-4 \)
Thus \(a-b=-2 \)
(other values for a and b will give similar result)
SUFF.
Ans D
Hope it helps.
02 Jul 2023, 09:31
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