Bunuel wrote:
Is x = y ?
(1) \(\frac{2x}{3} - \frac{y}{3} = \frac{1}{3}\)
(2) \(\frac{x}{4} - \frac{y}{4} = 0\)
Target question: Is x = y? Statement 1: \(\frac{2x}{3} - \frac{y}{3} = \frac{1}{3}\)
Multiply both sides by 3 to get: \(2x - y = 1\)
Rewrite as: \(y = 2x - 1\)
There are several values of x and y that satisfy the above equation. Here are two:
Case a: x = 1 and y = 1. In this case, the answer to the target question is
YES, x EQUALS yCase b: x = 3 and y = 5. In this case, the answer to the target question is
NO, x does NO equal ySince we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: \(\frac{x}{4} - \frac{y}{4} = 0\)
Multiply both sides by 4 to get: \(x - y = 0\)
Add y to both sides to get: \(x = y\)
PERFECT! The answer to the target question is
YES, x EQUALS ySince we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
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