It is currently 20 Jan 2018, 13:11

Close

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is the average (arithmetic mean) of a, b, and c greater than 12?

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43334

Kudos [?]: 139595 [0], given: 12794

Is the average (arithmetic mean) of a, b, and c greater than 12? [#permalink]

Show Tags

New post 01 Jan 2018, 00:30
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

79% (01:05) correct 21% (00:14) wrong based on 14 sessions

HideShow timer Statistics

Kudos [?]: 139595 [0], given: 12794

Expert Post
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 4692

Kudos [?]: 3323 [0], given: 0

GPA: 3.82
Premium Member
Re: Is the average (arithmetic mean) of a, b, and c greater than 12? [#permalink]

Show Tags

New post 02 Jan 2018, 12:12
Bunuel wrote:
Is the average (arithmetic mean) of a, b, and c greater than 12?

(1) c > a + b
(2) ac = 48



Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

Since we have 3 variables (x and y) and 0 equations, E is most likely to be the answer. So, we should consider 1) & 2) first.

Case 1: a = 1, b = 2 c = 48
( a + b + c ) / 3 = 51 / 3 > 12 : Yes

Case 2: a = 6, b = 1, c = 8
( a + b + c ) / 3 = 15 / 3 = 5 < 12 : No

The answer is E.

In cases where 3 or more additional equations are required, such as for original conditions with “3 variables”, or “4 variables and 1 equation”, or “5 variables and 2 equations”, conditions 1) and 2) usually supply only one additional equation. Therefore, there is an 80% chance that E is the answer, a 15% chance that C is the answer, and a 5% chance that the answer is A, B or D. Since E (i.e. conditions 1) & 2) are NOT sufficient, when taken together) is most likely to be the answer, it is generally most efficient to begin by checking the sufficiency of conditions 1) and 2), when taken together. Obviously, there may be occasions on which the answer is A, B, C or D.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Kudos [?]: 3323 [0], given: 0

Re: Is the average (arithmetic mean) of a, b, and c greater than 12?   [#permalink] 02 Jan 2018, 12:12
Display posts from previous: Sort by

Is the average (arithmetic mean) of a, b, and c greater than 12?

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


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.