of x, y, and z

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

of x, y, and z

by sanju09 » Sat Jul 24, 2010 4:13 am
Are the integers x, y, and z consecutive?

1. The arithmetic mean (average) of x, y, and z is y.
2. y - x = z - y.

[spoiler]Source: majortests.com[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Data Sufficiency |

Legendary Member
Posts: 759
Joined: Mon Apr 26, 2010 10:15 am
Thanked: 85 times
Followed by:3 members

by clock60 » Sat Jul 24, 2010 5:42 am
got E here
(1) (x+y+z)/3=y from here x+z=2y. and many versions are possible
y=1, x=1,z=1 not consecutive
y=2,x=1,z=3 consecutive
insufficient
(2)y-x=z-y, 2y=x+z the reasoning the same as for st 1
both insuffiicent

User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Sat Jul 24, 2010 6:16 am
1. The arithmetic mean (average) of x, y, and z is y.
2. y - x = z - y.


Stmt1,

x y z

Median=y

y=(x+y+z)/3

If the numbers are consecutive,mean of numbers is equal to median.

Sufficient.

Stmt2,

y - x = z - y.

2y=x+z

y=(x+z)/2

If the numbers are consecutive, median is equal to average of range.

Sufficient.

Hence D
--Anand--

User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

by sanju09 » Sat Jul 24, 2010 6:21 am
selango wrote:1. The arithmetic mean (average) of x, y, and z is y.
2. y - x = z - y.


Stmt1,

x y z

Median=y

y=(x+y+z)/3

If the numbers are consecutive,mean of numbers is equal to median.

Sufficient.

Stmt2,

y - x = z - y.

2y=x+z

y=(x+z)/2

If the numbers are consecutive, median is equal to average of range.

Sufficient.

Hence D
This is mere misinterpretation of the correct definitions of few mathematical terminologies.
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com

User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Sat Jul 24, 2010 6:31 am
oops..my mistake..

Got it..its works also for evenly spaced numbers.rt?
--Anand--

User avatar
Legendary Member
Posts: 748
Joined: Sun Jan 31, 2010 7:54 am
Thanked: 46 times
Followed by:3 members

by outreach » Sat Jul 24, 2010 7:33 am
1. The arithmetic mean (average) of x, y, and z is y.

(x+y+z)/3=y
x+z=2y

x z y
1 4 7 no corresponding num
3 4 5 corresponding num

insuff

2. y - x = z - y.
x+z=2y
x z y
1 4 7 no corresponding num
3 4 5 corresponding num

insuff


comb 1 and 2
insuff

sanju09 wrote:Are the integers x, y, and z consecutive?

1. The arithmetic mean (average) of x, y, and z is y.
2. y - x = z - y.

[spoiler]Source: majortests.com[/spoiler]
-------------------------------------
--------------------------------------
General blog
https://amarnaik.wordpress.com
MBA blog
https://amarrnaik.blocked/