Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 22 May 2015, 20:31

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Does the average (arithmetic mean) of a,b, and c equal c? 1.

Author Message
TAGS:
Senior Manager
Joined: 17 Aug 2005
Posts: 393
Location: Boston, MA
Followers: 1

Kudos [?]: 19 [0], given: 0

Does the average (arithmetic mean) of a,b, and c equal c? 1. [#permalink]  05 Jan 2006, 18:25
00:00

Difficulty:

(N/A)

Question Stats:

100% (01:07) correct 0% (00:00) wrong based on 1 sessions
Does the average (arithmetic mean) of a,b, and c equal c?

1. c-a = c+b
2. c=0

I'm sure this is a joke question for some of you but can someone dumb down their answer/explanation for me on this one? I don't know the best way to tackle it. And the kaplan explanation is just not sinking in. thanks...
 Kaplan GMAT Prep Discount Codes Knewton GMAT Discount Codes Manhattan GMAT Discount Codes
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5077
Location: Singapore
Followers: 22

Kudos [?]: 186 [0], given: 0

The question is asking whether (a+b+c)/3 = c --> a+b+c = 3c --> a+b=2c

(1) c-a = c+b -> a+b=0. If a+b =0, the average of a+b+c = c/3. So the average of a,b and c is not equal to c, unless c is 0. Since we do not know c, this statememtn is not sufficient.

(2) c = 0. Not sufficient as we do not know a and b.

Ans C

Last edited by ywilfred on 05 Jan 2006, 18:45, edited 1 time in total.
Senior Manager
Joined: 17 Aug 2005
Posts: 393
Location: Boston, MA
Followers: 1

Kudos [?]: 19 [0], given: 0

how do you get 2c=a+b for Statement 1? I got -a=b or a+b=0. Is it correct to say that Statement 1 is insufficient because it tells us nothing about C?

I am struggling so much with DS, I just can't wrap my head around the concepts of how to approach them.
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5077
Location: Singapore
Followers: 22

Kudos [?]: 186 [0], given: 0

buckkitty wrote:
how do you get 2c=a+b for Statement 1? I got -a=b or a+b=0. Is it correct to say that Statement 1 is insufficient because it tells us nothing about C?

I am struggling so much with DS, I just can't wrap my head around the concepts of how to approach them.

Sorry, made a mistake. I'll rework that and post again later.
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5077
Location: Singapore
Followers: 22

Kudos [?]: 186 [0], given: 0

I've edited my working and the answer is C. Is that what you got?
Senior Manager
Joined: 17 Aug 2005
Posts: 393
Location: Boston, MA
Followers: 1

Kudos [?]: 19 [0], given: 0

C is the OA. I understand your answer now. I was unsure why A was insuff. but now I get it.... thanks!
Senior Manager
Joined: 14 Apr 2005
Posts: 418
Location: India, Chennai
Followers: 1

Kudos [?]: 6 [0], given: 0

Re: DS-average from Kaplan workbook 4th ed. [#permalink]  05 Jan 2006, 22:58
buckkitty wrote:
Does the average (arithmetic mean) of a,b, and c equal c?

1. c-a = c+b
2. c=0

I'm sure this is a joke question for some of you but can someone dumb down their answer/explanation for me on this one? I don't know the best way to tackle it. And the kaplan explanation is just not sinking in. thanks...

We need to see if (a+b+c)/3 = c

From stmt 1 we get a+b=0, nothing is known about c so insuff.
From stmt 2 we get c = 0 but nothing is known about a,b so insuff.
Combing we have all information for a,b and c. So this is suff.

Hence C.
Re: DS-average from Kaplan workbook 4th ed.   [#permalink] 05 Jan 2006, 22:58
Similar topics Replies Last post
Similar
Topics:
2 What is the average (arithmetic mean) of A, B, and 4C? 3 20 Sep 2013, 05:53
The average (arithmetic mean) of a, b, c, d, e is 7. What is 2 28 Jul 2012, 14:28
What is the average (arithmetic mean) of 11 integers? (1) 1 12 Mar 2008, 12:04
What is the average (arithmetic mean) of a, b, and c? (1) 6 05 Dec 2005, 21:21
If a + b = 8c, what is the average (arithmetic mean) of a, 2 02 Oct 2005, 00:43
Display posts from previous: Sort by