Quantitative

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Quantitative

by John fran kennedi » Thu Mar 10, 2016 5:42 pm
Guys, I do need your explanations why the correct answer of this question is C

If the quotient a/b is less than zero, which of the following cannot be true?
A. a > 0
B. b > 0
C. ab > 0
D. a-b > 0
E. a+b > 0


As we know that if a is positive, b must be negative, vice versa.
Answer choices
A. If A can be negative , so it cannot be true that A > 0
B. It's same as the answer choice A
C. If A is positive and B is negative , it cannot be greater than 0
D. If A is -4 and B is 2, cannot be greater than 0
E. E is like D
Source: — Problem Solving |

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by [email protected] » Fri Mar 11, 2016 10:06 am
Hi John fran kennedi,

It looks like you've done all of the 'work' correctly here.

Since A/B is less than 0, then one of the variables is NEGATIVE and the other is POSITIVE. By definition:

(negative)(positive) = negative

Thus, (A)(B) can NEVER be greater than 0. The question asks what CANNOT be true - and you've proven that Answer C cannot be true.

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Rich
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by John fran kennedi » Sat Mar 12, 2016 12:07 am
Hi Rich.
Thank you so much. I do understand now.