Hi All,
This question is an example of a 'Symbolism' question; in these types of prompt, the GMAT 'makes up' a math symbol, tells you how to use it, then asks you to use it to perform a calculation.
Here, we're given a made-up calculation that uses the @ symbol....
A@B = (A-B)/(A+B)
eg.
1@2 = (1-2)/(1+2) = -1/3
We're told that A@C = 0 and A ≠ -C. We're asked for the value of C....
We can TEST VALUES to answer this question, but we have to start by TESTing a VALUE for A, then figure out what C would have to equal....
IF....
A = 2
A@C = 2@C = (2-C)/(2+C) = 0
So, what would C have to equal to make this equation equal 0?
(2-C)/(2+C) = 0
Since we're dealing with a fraction, we need the NUMERATOR to equal 0. In this example, that would ONLY happen when C = 2. So we're looking for an answer that equals 2 when A=2.
Answer A: - A = -2 NOT a match
Answer B: -1/A = -1/2 NOT a match
Answer C: 0 NOT a match
Answer D: 1/A = 1/2 NOT a match
Answer E: A = 2 This IS a MATCH
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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Contact Rich at: Rich.C@empowergmat.comThe Course Used By GMAT Club Moderators To Earn 750+ souvik101990 Score: 760 Q50 V42 ★★★★★ ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★