It is currently 17 Oct 2017, 15:55

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is x+y < 1 1) x < 8/9 2) y < 1/8 Need a fast way to

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Retired Moderator
User avatar
Joined: 18 Jul 2008
Posts: 962

Kudos [?]: 294 [0], given: 5

Is x+y < 1 1) x < 8/9 2) y < 1/8 Need a fast way to [#permalink]

Show Tags

New post 01 Dec 2008, 19:50
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is x+y < 1

1) x < 8/9

2) y < 1/8

Need a fast way to solve this.

Kudos [?]: 294 [0], given: 5

Expert Post
1 KUDOS received
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3584

Kudos [?]: 4576 [1], given: 360

Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
GMAT ToolKit User Premium Member
Re: DS [#permalink]

Show Tags

New post 02 Dec 2008, 05:27
1
This post received
KUDOS
Expert's post
10-sec method...

1. for negative x,y x+y is always less than 1
2. maximum value for x+y is (1/8+8/9). Is it larger than 1?
3. Think of following idea: 1/2<2/3<3/4<....7/8<8/9<9/10... Therefore, 1/8+8/9 > 1/8+7/8 ---> 1/8+8/9>1 ---> Answer is E.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Kudos [?]: 4576 [1], given: 360

Retired Moderator
User avatar
Joined: 18 Jul 2008
Posts: 962

Kudos [?]: 294 [0], given: 5

Re: DS [#permalink]

Show Tags

New post 02 Dec 2008, 11:34
Isn't C sufficient to solve this? Wouldn't the answer be always less than 1?

We can't use (8/9+1/8) to be the max because a) and b) specifically says that x is less than 8/9, and y is less than 1/8.

What I did was took the next highest number that satisfied X and Y

X = 7/8
Y = 1/9

Add them both and they are less than 1.

What's wrong with my method?

Kudos [?]: 294 [0], given: 5

SVP
SVP
avatar
Joined: 17 Jun 2008
Posts: 1535

Kudos [?]: 279 [0], given: 0

Re: DS [#permalink]

Show Tags

New post 02 Dec 2008, 12:29
You can add the two inequalities here (as the two inequalities have the same sign).

Hence, x + y < 8/9 + 1/8

Kudos [?]: 279 [0], given: 0

Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3584

Kudos [?]: 4576 [0], given: 360

Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
GMAT ToolKit User Premium Member
Re: DS [#permalink]

Show Tags

New post 02 Dec 2008, 12:36
bigfernhead wrote:
Isn't C sufficient to solve this? Wouldn't the answer be always less than 1?

We can't use (8/9+1/8) to be the max because a) and b) specifically says that x is less than 8/9, and y is less than 1/8.


I agree that x+y cannot be equal to (8/9+1/8) but x+y could be equal to (8/9+1/8)-0.00000000000000001
In other words, x+y<(8/9+1/8)

bigfernhead wrote:
What I did was took the next highest number that satisfied X and Y

X = 7/8
Y = 1/9

Add them both and they are less than 1.

What's wrong with my method?


You took too large step. You also could use a direct method without tricks: (8/9+1/8)=(64+9)/72=73/72>1. So, x+y could be 72.5/72>1
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Kudos [?]: 4576 [0], given: 360

Re: DS   [#permalink] 02 Dec 2008, 12:36
Display posts from previous: Sort by

Is x+y < 1 1) x < 8/9 2) y < 1/8 Need a fast way to

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.