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

It is currently 23 Oct 2014, 10:13

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

stamps

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 06 Nov 2008
Posts: 54
Followers: 0

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

stamps [#permalink] New post 11 Dec 2008, 17:36
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1) She bought $4.40 worth of stamps.
(2) She bought an equal number of $0.15 stamps and $0.29 stamps.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Manager
Manager
avatar
Joined: 27 May 2008
Posts: 204
Followers: 1

Kudos [?]: 16 [0], given: 0

Re: stamps [#permalink] New post 11 Dec 2008, 18:25
A

1) 0.15n + 0.29m = 4.4

The above condition holds true, only when n = m = 10.

Approach:

Usually in GMAT DS, option B is given to support or give additional clue for the option A to render the answer. Since ideally all GMAT questions real world questions i,e we get same answer for D using both the statement.(again most cases)

So by keeping this in mind, if u see option B it is giving addional clue to give solution, but if u see possible answers with option A, it can give answer only when both n=m.( since 29 is a prime and multiples of 15 cannot be equal to multiples 29 whose sum is 440).

Hope this helps some audience.
Intern
Intern
avatar
Joined: 05 Dec 2008
Posts: 20
Followers: 0

Kudos [?]: 2 [0], given: 0

Re: stamps [#permalink] New post 12 Dec 2008, 20:45
haichao wrote:
Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
(1) She bought $4.40 worth of stamps.
(2) She bought an equal number of $0.15 stamps and $0.29 stamps.


I thought it would be worth noting why statement one is enough information since it might not be obvious that the solution of ten 15-cent stamps and ten 29-cent stamps is the ONLY solution here.

Let's use cents rather than dollars.

The most important thing to notice here is that no matter how many 15-cent stamps I buy, their total value will always end in 5 or 0 (e.g., 15 cents, 30 cents, 45 cents, 60 cents etc). So, if we are to combine a certain number of 29-cent stamps, we need enough of them so that their total value ends in either 5 or 0 since all of the stamps are worth a nice tidy sum of 440 cents.

Under what circumstances will the total value of our 29-cent stamps end in either 5 or 0? When we have 0 stamps, 5 stamps, 10 stamps or 15 stamps. We need to check all four of these cases, since it might be possible that there are two or more ways to get 440 cents worth of stamps, in which case (1) would not be enough informaiton.
If we check four cases, only one case (ten 29-cent stamps combined with ten 10-cent stamps) will give us a sum of 440 cents.

This is why statement (1) provides enough information.

Statement (2) does not provide enough information.

The answer is A.
Re: stamps   [#permalink] 12 Dec 2008, 20:45
    Similar topics Author Replies Last post
Similar
Topics:
1 The number of stamps shanewyatt 2 20 Jan 2010, 17:12
1 stamps amychen77 7 17 Oct 2008, 09:20
PS: STAMPS el1981 2 25 Mar 2008, 18:24
Experts publish their posts in the topic number of stamps uphillclimb 12 13 Nov 2006, 19:25
stamps lan583 2 18 Oct 2006, 15:15
Display posts from previous: Sort by

stamps

  Question banks Downloads My Bookmarks Reviews Important topics  


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

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®.