Gmat_mission wrote:Is s = r ?
(1) s² = r²
(2) s is positive
Target question: Is s = r ?
Statement 1: s² = r²
This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several values of r and s that satisfy statement 1. Here are two:
Case a: r = 1 and s = 1. Notice that s² = r² becomes (1)² = (1)², which satisfies the statement 1. In this case,
the answer to the target question is YES, s equals r
Case b: r = -1 and s = 1. Notice that s² = r² becomes (-1)² = (1)², which satisfies the statement 1. In this case,
the answer to the target question is NO, s does NOT equal r
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: s is positive
Since this statement provides NO INFORMATION about the value of r, there's no way we can answer the
target question with certainty
So, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
There are several values of r and s that satisfy BOTH statements. Here are two:
Case a: r = 1 and s = 1. In this case,
the answer to the target question is YES, s equals r
Case b: r = -1 and s = 1. In this case,
the answer to the target question is NO, s does NOT equal r
Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer: E
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
