M07 q18 : Retired Discussions [Locked]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 16 Jan 2017, 14:40

### 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

# M07 q18

Author Message
Manager
Joined: 13 May 2010
Posts: 124
Followers: 0

Kudos [?]: 12 [0], given: 4

### Show Tags

22 Jun 2012, 04:41
1
This post was
BOOKMARKED
There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?

(1) From any two snakes from Pandora's box at least one is a viper.
(2) The total number of snakes Pandora's box is 99.

(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there can not be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient.

(2) The total number of snakes Pandora's box is 99. Clearly insufficient.

Can someone please explain me the solution?
Joined: 28 Mar 2012
Posts: 314
Location: India
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 29

Kudos [?]: 398 [1] , given: 23

### Show Tags

24 Jun 2012, 19:54
1
KUDOS
teal wrote:
There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?

(1) From any two snakes from Pandora's box at least one is a viper.
(2) The total number of snakes Pandora's box is 99.

(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there can not be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient.

(2) The total number of snakes Pandora's box is 99. Clearly insufficient.

Can someone please explain me the solution?

Hi,

Consider the following case, V-Viper, C- Cobra,
(C, C, V, V), from this we can have a pair (V, V), (C, V) which satisfy the condition given in statement 1.
but the pair (C, C) has no viper (there should be at least one viper in any pair!), so such pair is not possible.
Thus, there can be only 1 cobra, along with any number of vipers. Sufficient.

Regards,
Math Expert
Joined: 02 Sep 2009
Posts: 36520
Followers: 7066

Kudos [?]: 92911 [0], given: 10528

### Show Tags

22 Jun 2012, 04:48
teal wrote:
There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?

From any two snakes from Pandora's box at least one is a viper.
The total number of snakes Pandora's box is 99.

Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
EACH statement ALONE is sufficient
Statements (1) and (2) TOGETHER are NOT sufficient

(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there can not be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient.

(2) The total number of snakes Pandora's box is 99. Clearly insufficient.

Can someone please explain me the solution?

Can you please specify what didn't you understand?
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 36520
Followers: 7066

Kudos [?]: 92911 [0], given: 10528

### Show Tags

22 Jun 2012, 08:03
teal wrote:
There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?

(1) From any two snakes from Pandora's box at least one is a viper.
(2) The total number of snakes Pandora's box is 99.

(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there can not be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient.

(2) The total number of snakes Pandora's box is 99. Clearly insufficient.

Can someone please explain me the solution?

This question is also discussed in the following posts:
devil-s-dozen-129312-20.html?hilit=viper#p1063888
devil-s-dozen-129312-20.html?hilit=viper#p1064475

Hope it helps.
_________________
Manager
Joined: 06 Oct 2009
Posts: 105
Location: Mexico
Concentration: Entrepreneurship, Finance
GPA: 3.85
WE: Sales (Commercial Banking)
Followers: 1

Kudos [?]: 130 [0], given: 4

### Show Tags

10 Jul 2012, 03:16
I think this question could be enhanced if it states that the Pandora Box has only two kind of snakes.
Math Expert
Joined: 02 Sep 2009
Posts: 36520
Followers: 7066

Kudos [?]: 92911 [0], given: 10528

### Show Tags

10 Jul 2012, 03:26
Bull78 wrote:
I think this question could be enhanced if it states that the Pandora Box has only two kind of snakes.

That's not necessary at all. Check this: devil-s-dozen-129312-20.html?hilit=viper#p1064475
_________________
Manager
Joined: 06 Oct 2009
Posts: 105
Location: Mexico
Concentration: Entrepreneurship, Finance
GPA: 3.85
WE: Sales (Commercial Banking)
Followers: 1

Kudos [?]: 130 [0], given: 4

### Show Tags

10 Jul 2012, 03:49
Bunuel wrote:
Bull78 wrote:
I think this question could be enhanced if it states that the Pandora Box has only two kind of snakes.

That's not necessary at all. Check this: devil-s-dozen-129312-20.html?hilit=viper#p1064475

Many thanks Bunuel! U rule!
Re: M07 q18   [#permalink] 10 Jul 2012, 03:49
Similar topics Replies Last post
Similar
Topics:
20 M07 #2 15 25 Sep 2008, 10:35
3 m07 q33 10 08 Sep 2008, 10:39
6 m07 #22 19 03 Sep 2008, 18:41
M07: Q25 10 25 Aug 2008, 18:36
1 m07q18 16 23 Jul 2008, 04:58
Display posts from previous: Sort by

# M07 q18

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO 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®.