If r 0, is rs

Question

If r > 0, is rs < 0 ?

(1) s < 0

(2) s < r

Abhishiek · Answer

r<0 So rs<0 can be answered if s>0 or s<0. 1. Sufficient. 2. s could be <0 or >0. Not Sufficient. A.

Mo2men · Answer

r > 0 , then question might be rephrased to be, is  s < 0  ?

1) s < 0

The facts tells us a fact

Sufficient

(2) s < r

Let r =2 & s = 1......Answer is No

Let r =2 & s =-1......Answer is Yes

Insufficient

Answer: A

MathRevolution · Answer

Forget the conventional way to solve DS questions.

We will solve this DS question using the variable approach.

The first step of the Variable Approach: The first step and the priority is to modify and recheck the original condition and the question to suit the type of information given in the condition.

To master the Variable Approach, visit https://www.mathrevolution.com and check our lessons and proven techniques to score high in DS questions.

Learn the 3 steps. [Watch lessons on our website to master these 3 steps]

Step 1 of the Variable Approach: Modifying and rechecking the original condition and the question.

We have to find whether rs < 0.

=> It is given that r > 0 and if rs < 0, that means 's' should be negative [s < 0]

We have to find whether s < 0

Condition(1) tells us that s < 0.

=> Is s < 0 - YES

Since the answer is unique YES, condition(1) alone is sufficient by CMT 1.

Condition(2) tells us that s < r .

=> 's' could be [s < 0 or s > 0]

Since the answer is not a unique YES or NO ,condition(2) alone is not sufficient by CMT 1.

Condition(1) alone is sufficient.

So, A is the correct answer.

Answer: A

SAVE TIME: By Variable Approach[MODIFICATION], check the condition quickly and separately and mark answer as A or B.

bumpbot · Answer

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If r > 0, is rs < 0 ? (1) s < 0 (2) s < r

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