Bunuel
If \(x ≠ 0\) and \(p\) is an integer, then what is the value of \(x^p\) ?
(1) \(p = p^2\)
(2) \(p < 1\)
Target question: What is the value of \(x^p\) ?Aside: Some students will look at the statements and conclude that, since there's no information about x, the two statements combined must be insufficient.
However, if \(p = 0\), and \(x ≠ 0\), then \(x^p = x^0 = 1\).
So, if a statement shows that \(p\) must equal \(0\), then that statement will be sufficient. Statement 1: \(p = p^2\) Subtract \(p\) from both sides of the equation to get: \(0 = p^2 - p\)
Factor: \(0 = p(p-1)\)
So, EITHER \(p = 0\) OR \(p = 1\)
Case a: If \(p = 0\), then the answer to the target question is
\(x^p=x^0=1\) Case b: If \(p = 1\), then the answer to the target question is
\(x^p=x^1=x\) Since we can’t answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: \(p < 1\)Definitely not sufficient.
Statements 1 and 2 combined Statement 1 tells us that EITHER \(p = 0\) OR \(p = 1\)
Statement 2 tells us that \(p < 1\)
Since both statements must be considered true, it must be the case that \(p = 0\), which means
\(x^p=x^0=1\) Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C
Cheers,
Brent