November 17, 2018 November 17, 2018 07:00 AM PST 09:00 AM PST Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT. November 17, 2018 November 17, 2018 09:00 AM PST 11:00 AM PST Join the Quiz Saturday November 17th, 9 AM PST. The Quiz will last approximately 2 hours. Make sure you are on time or you will be at a disadvantage.
Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 27 Sep 2009
Posts: 40

A terminating decimal is defined as a decimal that has a
[#permalink]
Show Tags
22 May 2010, 13:35
Question Stats:
80% (00:38) correct 20% (01:09) wrong based on 856 sessions
HideShow timer Statistics
A terminating decimal is defined as a decimal that has a finite number of nonzero digits. Examples of terminating decimals are 0.24, 52, and 6.0314. x and y are positive integers. If x/y is expressed as a decimal, is it a terminating decimal? (1) 40 < x < 45 (2) y = 8
Official Answer and Stats are available only to registered users. Register/ Login.




Math Expert
Joined: 02 Sep 2009
Posts: 50619

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 15:46
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 nonnegative integers. For example: \(\frac{7}{250}\) is a terminating decimal \(0.028\), as \(250\) (denominator) equals to \(2*5^3\). 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 2s and/or 5s 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 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.) In original question statement (2) says that denominator equals to 2^3=8, hence x/8 will be terminating decimal no matter what the value of x is.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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? Extrahard Quant Tests with Brilliant Analytics




Manager
Joined: 16 Mar 2010
Posts: 112
Location: Halifax, Canada
Schools: Dalhousie School of Business (Corporate Residency MBA)

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 13:54
(1) Definitely isn't enough, because you can tweak the denominator any way you like to arrive at fraction that simplifies down to say, 2/3 (0.66666...) (2) Is the same thing.
At first glance this question seems really too easy. You need to know what's going on with both x and y in order be able to answer it.
C) jumps out immediately. It's obvious that if you know even the ranges of both x and y you could test each combo out and eventually arrive at an answer so clearly taken together they are sufficient.
It's just a matter of seeing if A, B or D is feasible. I don't think they are for the reasons I gave above. If I only know either the nominator or denominator, I can find a match somewhere down the line that allows to make it so the simplified result ends up to be 2/3 (recurring decimal) or 1/1 (obviously a terminating one).
So: C



Intern
Joined: 27 Sep 2009
Posts: 40

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 14:08
dalmba wrote: (1) Definitely isn't enough, because you can tweak the denominator any way you like to arrive at fraction that simplifies down to say, 2/3 (0.66666...) (2) Is the same thing.
At first glance this question seems really too easy. You need to know what's going on with both x and y in order be able to answer it.
C) jumps out immediately. It's obvious that if you know even the ranges of both x and y you could test each combo out and eventually arrive at an answer so clearly taken together they are sufficient.
It's just a matter of seeing if A, B or D is feasible. I don't think they are for the reasons I gave above. If I only know either the nominator or denominator, I can find a match somewhere down the line that allows to make it so the simplified result ends up to be 2/3 (recurring decimal) or 1/1 (obviously a terminating one).
So: C OA is B Statement (2): Any number divided by 8 results in a terminating decimal. This is because when a number is divided by 2, the only possible remainders are or 1, 2, 3, 4, 5, 6, and 7 (actually 1/8, 2/8, etc.). These remainders are expressed as .125, .25, .375, .5, .625, .75, and .875, respectively. Therefore x/y is a terminating decimal; SUFFICIENT. I did not understand this... could u please help me



Manager
Joined: 16 Mar 2010
Posts: 112
Location: Halifax, Canada
Schools: Dalhousie School of Business (Corporate Residency MBA)

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 14:33
Haha, this is why I'm bad at DS. You're supposed to intuitively know that anything ever divided by 8 will result in a terminal decimal. I messed up in assuming I had control over the denominator (when I said (2) is the same logic as why (1) doesn't work), when it clearly said it was 8 and nothing else. It's funny, the last DS question I answered here I got right but made a big deal about feeling reluctant to toss out B. I was right to be feeling that way, but just not for the correct question. *sigh*



VP
Status: mission completed!
Joined: 02 Jul 2009
Posts: 1289
GPA: 3.77

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 14:50
shekar123 wrote: A terminating decimal is defined as a decimal that has a finite number of nonzero digits. Examples of terminating decimals are 0.24, 52, and 6.0314. x and y are positive integers. If x/y is expressed as a decimal, is it a terminating decimal?
(1) 40 < x < 45
(2) y = 8 B. any positive integer number divided by 8 gives terminate decimal equal to 5. 1) is very alluring, cause we read 1) and then 2), having in mind "I dont know x, so I cant find out what is the decimal point, thus I need to know the range of numbers for X" Thus c is wrong.
_________________
Audaces fortuna juvat!
GMAT Club Premium Membership  big benefits and savings



Manager
Joined: 16 Mar 2010
Posts: 112
Location: Halifax, Canada
Schools: Dalhousie School of Business (Corporate Residency MBA)

Re: 700+ question
[#permalink]
Show Tags
22 May 2010, 16:05
Bunuel wrote: For example \(\frac{x}{2^n5^m}\), (where x, n and m are integers) will always be terminating decimal.
That is sweet. A nifty little tool that's not too horrible to remember. Also, in order to preserve some sort of semblance of competency in this realm I will quite proudly point out that there was a typo in your post here: Bunuel wrote: as \(250\) (denominator) equals to \(2*5^2\). As it should read  "\(250\) (denominator) equals to \(2*5^ 3\)"



Senior Manager
Affiliations: SPG
Joined: 15 Nov 2006
Posts: 302

Re: 600 + question
[#permalink]
Show Tags
22 May 2010, 20:58
shekar123 wrote: A terminating decimal is defined as a decimal that has a finite number of nonzero digits. Examples of terminating decimals are 0.24, 52, and 6.0314. x and y are positive integers. If x/y is expressed as a decimal, is it a terminating decimal?
(1) 40 < x < 45
(2) y = 8 1) we don't know anything about y, so Insufficient 2) when you divide anything by 8 the answer will be either an integer, a fraction of a multiple of 0.125. For example 201/8 = 25.125 and 203/8 = 25.375 So in any case, this will always lead to a terminating decimal. Sufficient My Answer: B



Intern
Joined: 31 Aug 2011
Posts: 1

Re: A terminating decimal is defined as a decimal that has a
[#permalink]
Show Tags
24 Apr 2012, 03:20
Found this helpful explanation on Mgmat site. Author Emily Sledge This rule took a while for me to internalize. It's tough to picture a decimal terminating when the denominator is so huge, such as DWG's example of 43/256. I found it helped me to think about the basic patterns: 1/2^1 = 0.5 1/2^2 = 0.25 1/2^3 = 0.125 1/2^4 = 0.0625 1/2^5 = 0.03125 1/2^6 = 0.015625 1/2^7 = 0.0078125 1/5^1 = 0.2 1/5^2 = 0.04 1/5^3 = 0.008 1/5^4 = 0.0016 1/5^5 = 0.00032 1/5^6 = 0.000064 1/5^7 = 0.0000128 Every one of these terminates, and the pattern indicates that would continue to be true for higher powers. The number of decimal places increases along with the powers of 2 or 5, but the number of decimal places will always be finite. In contrast, any factors other than 2 or 5 in the denominator can quickly be shown to be nonterminating, even for the most basic case (exponent of 1). Higher powers would be even messier: 1/3 = 0.33333(3 repeating) 1/6 = 0.16666(6 repeating) 1/7 = 0.142857(142857 repeating) 1/9 = 0.11111(1 repeating)



Director
Joined: 24 Nov 2015
Posts: 522
Location: United States (LA)

Re: A terminating decimal is defined as a decimal that has a
[#permalink]
Show Tags
27 Apr 2016, 13:43
In statement 1 x can be 41,42,43 or 44. insufficient as we don't have value of y
In statement 2, clearly y is given as 8 which is the denominator of the fraction x/y. we know that any number which has denominator as 8 will be a terminating decimal
so correct answer  B



NonHuman User
Joined: 09 Sep 2013
Posts: 8786

Re: A terminating decimal is defined as a decimal that has a
[#permalink]
Show Tags
13 Sep 2018, 02:22
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




Re: A terminating decimal is defined as a decimal that has a &nbs
[#permalink]
13 Sep 2018, 02:22






