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

 It is currently 31 Jul 2015, 22:38

### 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

# Number Properties question (arithmetic mean)

Author Message
TAGS:
Intern
Joined: 06 Oct 2009
Posts: 33
Schools: Ryerson University
Followers: 1

Kudos [?]: 7 [0], given: 7

Number Properties question (arithmetic mean) [#permalink]  01 Feb 2010, 16:51
00:00

Difficulty:

(N/A)

Question Stats:

83% (01:21) correct 17% (00:51) wrong based on 8 sessions
If the average (arithmetic mean) of x and y is 60 and the average (arithmetic mean) of y and z is 80, what is the value of $$z - x$$?

(a) 70
(b) 40
(c) 20
(d) 10
(e) It cannot be determined from the information given.
Manager
Joined: 02 Aug 2009
Posts: 111
Followers: 2

Kudos [?]: 14 [0], given: 1

Re: Number Properties question (arithmetic mean) [#permalink]  01 Feb 2010, 16:55
(X + Y)/2=60 (Z + Y)/2=80

So Z + Y=160
X+Y = 120
Subtract the equations

and we get Z - X (the Y's cancel) = 40

Hope that helps
Manager
Status: Getting ready for the internship summer
Joined: 07 Jun 2009
Posts: 51
Location: Rochester, NY
Schools: Simon
WE 1: JPM - Treasury
Followers: 0

Kudos [?]: 21 [0], given: 23

Re: Number Properties question (arithmetic mean) [#permalink]  01 Feb 2010, 17:03
Write out the equations:

x + y = 120
y + z = 160

Get y alone:

y = 160 - z
y = 120 - x

Set them equal to one another and (z - x) appears:

160 - z = 120 - x
40 = z - x

Director
Joined: 03 Sep 2006
Posts: 884
Followers: 6

Kudos [?]: 307 [0], given: 33

Re: Number Properties question (arithmetic mean) [#permalink]  01 Feb 2010, 20:45
roceeet wrote:
If the average (arithmetic mean) of x and y is 60 and the average (arithmetic mean) of y and z is 80, what is the value of $$z - x$$?

(a) 70
(b) 40
(c) 20
(d) 10
(e) It cannot be determined from the information given.

x+y= 120 & y+z = 160

z-x = 160-120 = 40

Therefore "B"
Current Student
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2799
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 198

Kudos [?]: 1183 [0], given: 235

Re: Number Properties question (arithmetic mean) [#permalink]  02 Feb 2010, 09:22
Intern
Joined: 06 Oct 2009
Posts: 33
Schools: Ryerson University
Followers: 1

Kudos [?]: 7 [0], given: 7

Re: Number Properties question (arithmetic mean) [#permalink]  02 Feb 2010, 14:50
thanks for the replies.
Re: Number Properties question (arithmetic mean)   [#permalink] 02 Feb 2010, 14:50
Similar topics Replies Last post
Similar
Topics:
5 The ratio of the arithmetic mean of two numbers to 3 10 Nov 2012, 13:37
ANOTHER number properties question 3 06 Apr 2011, 15:30
Number properties question 11 06 Apr 2011, 15:18
Number properties (question 4) 3 16 Oct 2010, 23:41
5 Number properties question 24 26 Jan 2010, 12:02
Display posts from previous: Sort by