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:

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Brent Hanneson – Founder of gmatprepnow.com