Positive and Negative

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If a is negative, is b positive?

(1)

(2)

Review: Positive and Negative




Explanation

We are told that a is negative. Our mission is to attempt to determine definitively whether b is positive or not. On to the statements, separately first.

Statement (1) tells us that is negative. As examining cases can confirm, we can conclude that b is positive. Otherwise dividing a, which is negative, by b would violate the statement. Therefore Statement (1) is sufficient.

Statement (2) can be simplified by multiplying by 2 and adding a to both sides, yielding . We could meet that condition with a case in which b is positive, and also in another case in which b is negative but still greater than a. Therefore, Statement (2) is insufficient.

The correct answer is (A).


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