Bunuel wrote:
Is zp negative?
(1) pz^4 < 0
(2) p + z^4 = 14
Kudos for a correct solution.
Target question: Is zp negative? Statement 1: p(z^4) < 0 This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several values of p and z that satisfy statement 1. Here are two:
Case a: p = -1 and z = 1. In this case, pz = (-1)(1) = -1. So,
pz IS negative. Case b: p = -1 and z = -1. In this case, pz = (-1)(-1) = 1. So,
pz is NOT negative. Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: p + (z^4) = 14 There are several values of p and z that satisfy statement 1. Here are two:
Case a: p = -2 and z = 2. In this case, pz = (-2)(2) = -4. So,
pz IS negative. Case b: p = -2 and z = -2. In this case, pz = (-2)(-2) = 4. So,
pz is NOT negative. Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined There are still several values of p and z that satisfy BOTH statements. Here are two:
Case a: p = -2 and z = 2. In this case, pz = (-2)(2) = -4. So,
pz IS negative. Case b: p = -2 and z = -2. In this case, pz = (-2)(-2) = 4. So,
pz is NOT negative. Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer:
_________________
Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
Students often get questions wrong NOT because they lack the skills to solve the question, but because they don’t understand what the GMAT is testing Learn more