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

 It is currently 20 Aug 2019, 07:14 ### 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
Your Progress

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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. ### Request Expert Reply # a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 57152
a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value  [#permalink]

### Show Tags 00:00

Difficulty:   15% (low)

Question Stats: 88% (00:30) correct 13% (00:39) wrong based on 24 sessions

### HideShow timer Statistics

$$a \circ b = \frac{ab}{a+b}$$ for all a, b that satisfy $$a ≠ -b$$. What is the value of $$(–4) \circ 2$$?

A. $$-4$$

B. $$-2$$

C. $$-\frac{4}{3}$$

D. $$\frac{4}{3}$$

E. $$4$$

_________________
Director  G
Joined: 03 Jun 2019
Posts: 950
Location: India
a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value  [#permalink]

### Show Tags

Bunuel wrote:
$$a \circ b = \frac{ab}{a+b}$$ for all a, b that satisfy $$a ≠ -b$$. What is the value of $$(–4) \circ 2$$?

A. $$-4$$

B. $$-2$$

C. $$-\frac{4}{3}$$

D. $$\frac{4}{3}$$

E. $$4$$

Given: $$a \circ b = \frac{ab}{a+b}$$ for all a, b that satisfy $$a ≠ -b$$.
Asked: What is the value of $$(–4) \circ 2$$?

$$(–4) \circ 2 = \frac{(-4)*2}{-4+2}= \frac{-8}{-2} = 4$$

IMO E
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com
e-GMAT Representative V
Joined: 04 Jan 2015
Posts: 3019
Re: a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value  [#permalink]

### Show Tags

Solution

Given:
• $$a ∘ b = \frac{ab}{a+b}$$
• a ≠ −b

To find:
• The value of (–4)∘2

Approach and Working Out:
• $$(–4)∘2 = \frac{-4*2}{(-4 + 2)} = \frac{-8}{-2} = 4$$

Hence, the correct answer is Option E.

Answer: E

_________________ Re: a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value   [#permalink] 23 Jul 2019, 04:34
Display posts from previous: Sort by

# a*b = ab/(a + b) for all a, b that satisfy a ≠ -b. What is the value

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

#### MBA Resources  