GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 18 Sep 2018, 06:56

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

If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Manager
Manager
User avatar
S
Joined: 31 May 2015
Posts: 84
GMAT ToolKit User
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post Updated on: 22 Jun 2015, 02:47
27
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

63% (01:42) correct 37% (01:46) wrong based on 382 sessions

HideShow timer Statistics

If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct nonzero digits will x have?

A. One
B. Two
C. Three
D. Seven
E. Ten

_________________

GMAT loosers are born not made !!!


Originally posted by sony1000 on 22 Jun 2015, 01:02.
Last edited by Bunuel on 22 Jun 2015, 02:47, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
Most Helpful Expert Reply
GMAT Tutor
avatar
S
Joined: 24 Jun 2008
Posts: 1345
Re: If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 22 Jun 2015, 01:41
5
6
You don't really need to do long division here if you don't want to, as long as you know that 1/9 = 0.11111....., and 2/9 = 0.22222...., and so on.

If we multiply a number by 10, or by 100, or by any other power of 10, we're just moving the decimal point over. We won't change the number of distinct nonzero digits we have in our number. So we can freely multiply the fraction by any power of 10 without changing the answer. We can start by multiplying the fraction by 10^2 = 2^2 * 5^2, to get:

1/3^2*4^2

which is already a bit simpler. But we can keep going - we can multiply by 100^2 = (4*25)^2 = 4^2 * 25^2 to get the 4s out of the denominator as well. So this fraction

25^2/3^2 = 625/9

has the same number of distinct digits as the fraction in the question. Since 630/9 = 70, then 621/9 = 69, so 625/9 = 69 + 4/9 = 69.44444..... which has three distinct digits.

But I think most people would just do long division, either with 1/144, or with 1/14,400, which will also work, and probably is just as fast. I hate doing long division so I always look for another way!
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

General Discussion
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49204
Re: If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 22 Jun 2015, 02:55
sony1000 wrote:
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct nonzero digits will x have?

A. One
B. Two
C. Three
D. Seven
E. Ten


Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to rules 3, 7 and 10. Thank you.



Similar questions to practice:
if-3-4-2-3-5-6-is-expressed-as-a-terminating-decimal-how-many-nonze-198180.html
if-d-1-2-3-5-7-is-expressed-as-a-terminating-decimal-how-144440.html
if-t-1-2-9-5-3-is-expressed-as-a-terminating-decimal-ho-129447.html
if-1-2-11-5-17-is-expressed-as-a-terminating-decimal-ho-123889.html

Hope it helps.
_________________

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?
Extra-hard Quant Tests with Brilliant Analytics

Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8278
Location: Pune, India
Re: If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 22 Jun 2015, 22:32
5
3
sony1000 wrote:
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct nonzero digits will x have?

A. One
B. Two
C. Three
D. Seven
E. Ten


\(\frac{1}{(2^2*3^2*4^2*5^2)}\) = \(\frac{1}{2^2} * \frac{1}{3^2} * \frac{1}{4^2} * \frac{1}{5^2}= \frac{1}{100} * \frac{1}{9} * \frac{1}{16}\)

= \((.01 * .0625) * \frac{1}{9}\) (division by 9 leads to a non-terminating decimal so leave it for the end)

= .000625/9

= .0000694444...

So we have 3 distinct non zero digits.

Answer (C)
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Senior Manager
Senior Manager
avatar
S
Joined: 29 Jun 2017
Posts: 423
Re: If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 02 Oct 2017, 09:32
sony1000 wrote:
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct nonzero digits will x have?

A. One
B. Two
C. Three
D. Seven
E. Ten


we try to make dominator the multiple of 10,
so we multiple with 5^4

we have 5^4/9, we do not care how many 10 factors are there is the dominator

divide
694444444

so, there is only 3 distict

tricky
Manager
Manager
User avatar
S
Joined: 02 Aug 2017
Posts: 70
Concentration: Strategy, Nonprofit
Schools: ISB '20
GPA: 3.71
Re: If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 08 Aug 2018, 22:16
sony1000 wrote:
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct nonzero digits will x have?

A. One
B. Two
C. Three
D. Seven
E. Ten


Following is the simple calculation.

Posted from my mobile device
Attachments

15337917795822711816785492444616.jpg
15337917795822711816785492444616.jpg [ 1.69 MiB | Viewed 857 times ]


_________________


Everything is in flux, nothing stays still


MGMAT1 :590 Q42 V30 (07/07/18)
VERITAS :660 Q48 V33 (16/07/18)
GMATPREP1 :690 Q46 V36 (22/07/18)
GMATPREP2 :740 Q51 V39 (06/08/18)
ECONOMIST :740 Q49 V44 (11/08/18)
KAPLAN :690 Q49 V36 (17/08/18)
PRINCETON :690 Q48 V38 (26/08/18)
MGMAT2 :720 Q43 V45 (02/09/18)

Intern
Intern
avatar
B
Joined: 20 Jul 2018
Posts: 22
If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct  [#permalink]

Show Tags

New post 25 Aug 2018, 14:10
Took 01:02.

1st) do some fast math in your head: 4*9*16*25 = 64 * 225 = 10* 225 + 50* 225 + 4 * 225 = 2250 + 50*200 + 50*25 + 900 = 12250 + 1250 + 900 = 14 400 (or: 100*16*10 - 1600 = 16000 - 1600 = 14400)
2nd) switch the fraction into a decimal
done

the easy way.
_________________

Going to take the real test in November...

21.07.2018 OG gmat prep 400 (Q26,V20)
28.07.2018 OG gmat prep 550 (Q42,V23)
04.08.2018 MGMAT 680 (Q50,V31)
12.08.2018 MGMAT 680 (Q49, V33)

If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct &nbs [#permalink] 25 Aug 2018, 14:10
Display posts from previous: Sort by

If x= 1/(2^2*3^2*4^2*5^2) is expressed as a decimal, how many distinct

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.