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

It is currently 09 Jul 2014, 18:50

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

Which of the following fractions has a decimal equivalent th

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
2 KUDOS received
Manager
Manager
avatar
Joined: 06 May 2009
Posts: 78
Followers: 2

Kudos [?]: 7 [2] , given: 3

Which of the following fractions has a decimal equivalent th [#permalink] New post 09 Jul 2009, 09:29
2
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

54% (01:46) correct 45% (00:46) wrong based on 71 sessions
Which of the following fractions has a decimal equivalent that is a terminating decimal?

A. 10/189
B. 15/196
C. 16/225
D. 25/144
E. 39/128

OPEN DISCUSSION OF THIS QUESTION IS HERE: which-of-the-following-fractions-has-a-decimal-equivalent-159322.html
[Reveal] Spoiler: OA

Last edited by Bunuel on 01 Oct 2013, 06:37, edited 1 time in total.
Added the OA.
Kaplan Promo CodeKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
10 KUDOS received
Current Student
User avatar
Joined: 03 Aug 2006
Posts: 117
Location: Next to Google
Schools: Haas School of Business
Followers: 4

Kudos [?]: 95 [10] , given: 3

GMAT Tests User
Re: decimal equivalent [#permalink] New post 09 Jul 2009, 09:56
10
This post received
KUDOS
The answer is E.

For a fraction to be a terminating decimal the denominator can contain only the prime factors 2 and/or 5 i.e. the denominator should be in the form 2^a5^b

Looking at each denominator.

A. 189 has the prime factor 3 so the fraction is not a terminating decimal.
B. 196 has the prime factor 7 so the fraction is not a terminating decimal.
C. 225 has the prime factor 3 so the fraction is not a terminating decimal.
D. 144 has the prime factor 3 so the fraction is not a terminating decimal.
E. 128 has the prime factor 2 only and can be written in the form 2^75^0 which makes the fraction a terminating decimal.
Manager
Manager
avatar
Joined: 06 May 2009
Posts: 78
Followers: 2

Kudos [?]: 7 [0], given: 3

Re: decimal equivalent [#permalink] New post 09 Jul 2009, 09:58
Thanks a lot.
Nice explanation.
5 KUDOS received
Manager
Manager
avatar
Joined: 15 Apr 2008
Posts: 50
Location: Moscow
Followers: 0

Kudos [?]: 12 [5] , given: 8

Re: decimal equivalent [#permalink] New post 09 Jul 2009, 10:28
5
This post received
KUDOS
One important point: you should look at numerator as well, as it can simplify denominator. For example, 18/225 is a terminating decimal: 18/225=\frac{3*3*2}{3*3*5*5}=\frac{2}{5*5}.
However, this problem doesn't try to trick you this way.
SVP
SVP
User avatar
Joined: 09 Sep 2013
Posts: 1527
Followers: 153

Kudos [?]: 32 [0], given: 0

Premium Member
Re: decimal equivalent [#permalink] New post 01 Oct 2013, 06:34
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Expert Post
7 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18474
Followers: 3184

Kudos [?]: 21141 [7] , given: 2532

Re: Which of the following fractions has a decimal equivalent th [#permalink] New post 01 Oct 2013, 06:38
7
This post received
KUDOS
Expert's post
Which of the following fractions has a decimal equivalent that is a terminating decimal?
A. 10/189
B. 15/196
C. 16/225
D. 25/144
E. 39/128

THEORY:
Reduced fraction \frac{a}{b} (meaning that fraction is already reduced to its lowest term) can be expressed as terminating decimal if and only b (denominator) is of the form 2^n5^m, where m and n are non-negative integers. For example: \frac{7}{250} is a terminating decimal 0.028, as 250 (denominator) equals to 2*5^2. Fraction \frac{3}{30} is also a terminating decimal, as \frac{3}{30}=\frac{1}{10} and denominator 10=2*5.

Note that if denominator already has only 2-s and/or 5-s then it doesn't matter whether the fraction is reduced or not.

For example \frac{x}{2^n5^m}, (where x, n and m are integers) will always be the terminating decimal.

We need reducing in case when we have the prime in denominator other then 2 or 5 to see whether it could be reduced. For example fraction \frac{6}{15} has 3 as prime in denominator and we need to know if it can be reduced.

BACK TO THE QUESTION:

Only option E (when reduced to its lowest form) has the denominator of the form 2^n5^m: 39/128=39/2^7.

Answer: E.

Questions testing this concept:
does-the-decimal-equivalent-of-p-q-where-p-and-q-are-89566.html
any-decimal-that-has-only-a-finite-number-of-nonzero-digits-101964.html
if-a-b-c-d-and-e-are-integers-and-p-2-a3-b-and-q-2-c3-d5-e-is-p-q-a-terminating-decimal-125789.html
700-question-94641.html
is-r-s2-is-a-terminating-decimal-91360.html
pl-explain-89566.html
which-of-the-following-fractions-88937.html

OPEN DISCUSSION OF THIS QUESTION IS HERE: which-of-the-following-fractions-has-a-decimal-equivalent-159322.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: Which of the following fractions has a decimal equivalent th   [#permalink] 01 Oct 2013, 06:38
    Similar topics Author Replies Last post
Similar
Topics:
Which of the following fractions has a decimal equivalent th Dmitriy 0 27 Sep 2013, 07:34
3 Experts publish their posts in the topic Which of the following fractions has a decimal equivalent th TriColor 10 22 Aug 2009, 10:09
Which of the following fractions has a decimal equivalent nocilis 6 04 Feb 2005, 21:42
Which of the following fractions has a decimal equivalent crackgmat04 3 08 Dec 2004, 03:22
Which of the following fractions has a decimal equivalent saurya_s 13 25 Sep 2004, 15:02
Display posts from previous: Sort by

Which of the following fractions has a decimal equivalent th

  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®.