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

00:00

A

B

C

D

E

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...

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.

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.

gmatclubot

Re: DS-average from Kaplan workbook 4th ed.
[#permalink]
05 Jan 2006, 22:58