GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Jun 2019, 08:36

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# If ab > 0 and a < 0, which of the following is negative?

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 55668
If ab > 0 and a < 0, which of the following is negative?  [#permalink]

### Show Tags

06 Mar 2018, 21:42
00:00

Difficulty:

15% (low)

Question Stats:

85% (00:29) correct 15% (00:33) wrong based on 36 sessions

### HideShow timer Statistics

If ab > 0 and a < 0, which of the following is negative?

A) b

B) -b

C) -a

D) a/b

E) -(a + b)

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 55668
Re: If ab > 0 and a < 0, which of the following is negative?  [#permalink]

### Show Tags

06 Mar 2018, 21:42
Senior SC Moderator
Joined: 22 May 2016
Posts: 2899
If ab > 0 and a < 0, which of the following is negative?  [#permalink]

### Show Tags

07 Mar 2018, 15:20
Bunuel wrote:
If ab > 0 and a < 0, which of the following is negative?

A) b

B) -b

C) -a

D) a/b

E) -(a + b)

Number theory
Given: $$ab > 0$$

Result? $$a$$ and $$b$$ have the same sign.
Either both are negative, or both are positive.
(-2)*(-3) = 6
(2)*(3) = 6

Given: $$a < 0$$

$$a$$
is negative.

The variables have the same sign.
$$b$$ must also be negative.

a < 0
Let a = -6
ab > 0
Let ab = 18
(-6)(b) = 18
b = -3

A) b
b = -3. Negative. Correct. Keep.

B) -b
-b = -(-3) = 3. Positive. Reject.

C) -a
a = -6. -a = -(-6) = 6. Positive. Reject.

D) a/b
-6/-3 = 2. Positive. Reject.
(if the product of two numbers is positive, the quotient of two numbers will be positive).

E) -(a + b)
-(-6 +(-3)) =
-(-6 - 3) =
-(-9) = 9. Positive. Reject.
_________________
SC Butler has resumed!
Get two SC questions to practice, whose links you can find by date, here.

Tell me, what is it you plan to do with your one wild and precious life? -- Mary Oliver
If ab > 0 and a < 0, which of the following is negative?   [#permalink] 07 Mar 2018, 15:20
Display posts from previous: Sort by