DS from gmatclub

This topic has expert replies
User avatar
Legendary Member
Posts: 752
Joined: Sun Sep 12, 2010 2:47 am
Thanked: 20 times
Followed by:10 members
GMAT Score:700

DS from gmatclub

by prachich1987 » Sat Jan 01, 2011 2:24 am
If in number 0.xyz, x,y and z stand respectively for the first, second, and third digit to the right of the decimal point, is 0.xyz>(2/3)

1) x+y>13
2) x+z>14
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Sat Jan 01, 2011 4:37 am
prachich1987 wrote:If in number 0.xyz, x,y and z stand respectively for the first, second, and third digit to the right of the decimal point, is 0.xyz>(2/3)

1) x+y>13
2) x+z>14
2/3 = 0.6666...

Statement 1: (x + y) > 13
Possible pairs of values of (x ,y) are : (5, 9), (6, 8), (6, 9) etc
For (5, 9) => 0.xyz = 0.59z < 2/3
For (6, 8) = > 0.xyz = 0.68z > 2/3

Not Sufficient

Statement 1: (x + z) > 14
Possible pairs of values of (x ,z) are : (6, 9), (7, 8), (7, 9) etc
For (6, 9), if y = 1 => 0.xyz = 0.619 < 2/3
For (6, 9), if y = 9 => 0.xyz = 0.699 > 2/3

Not Sufficient


1 & 2 Together: Possible pairs of values of (x , y, z) are : (6, 8, 9), (6, 9 , 9), (7, 7, 8) etc. For all of them 0.xyz > 2/3

Sufficient

The correct answer is C.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Sat Jan 01, 2011 4:59 am
prachich1987 wrote:If in number 0.xyz, x,y and z stand respectively for the first, second, and third digit to the right of the decimal point, is 0.xyz>(2/3)

1) x+y>13
2) x+z>14
Statement 1:
Tells us that x≥5 (because the greatest possible value of y is 9, and if x=4 and y=9, then x+y = 4+9 = 13, and statement 1 indicates that x+y>13.)
If x=5, y=9, and z=1, is .591>.666? No.
If x=6, y=8, and z=1, is .681>.666? Yes.
Since the answer can be both no and yes, insufficient.

Statement 2:
Tells us that x≥6 (because the greatest possible value of z is 9, and if x=5 and z=9, then x+y = 5+9 = 14, and statement 2 indicates that x+z>14.)
If x=6, y=1, and z=9, is .619>.666? No.
If x=6, y=8, and z=9, is .689>.666? Yes.
Since the answer can be both no and yes, insufficient.

Statements 1 and 2 together:
Statement 2 tells us that x≥6.
Since statement 1 indicates that x+y>13, if x=6, then y≥8.
Since statement 2 indicates that x+z>14, if x=6, then z=9.
Thus, the smallest possible value of .xyz is .689.
Since .689>.666, we know that .xyz>.666.
Sufficient.

The correct answer is C.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3