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

It is currently 17 Nov 2018, 13:35

Gmatbusters' Weekly Quant Quiz

Join here 


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
Events & Promotions in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • FREE Quant Workshop by e-GMAT!

     November 18, 2018

     November 18, 2018

     07:00 AM PST

     09:00 AM PST

    Get personalized insights on how to achieve your Target Quant Score. November 18th, 7 AM PST
  • How to QUICKLY Solve GMAT Questions - GMAT Club Chat

     November 20, 2018

     November 20, 2018

     09:00 AM PST

     10:00 AM PST

    The reward for signing up with the registration form and attending the chat is: 6 free examPAL quizzes to practice your new skills after the chat.

How many consecutive zeros will appear at the end of 43! if that numbe

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

Hide Tags

Manager
Manager
avatar
Joined: 23 Sep 2016
Posts: 95
How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 02 Dec 2016, 13:09
4
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

67% (00:42) correct 33% (01:25) wrong based on 134 sessions

HideShow timer Statistics

How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?

A) 12
B) 11
C) 10
D) 9
E) 8
Senior Manager
Senior Manager
avatar
B
Joined: 13 Oct 2016
Posts: 367
GPA: 3.98
Re: How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 02 Dec 2016, 22:14
\(\frac{43}{5} + \frac{43}{5^2} = 8 + 1 = 9\)

Answer D
Intern
Intern
avatar
Joined: 18 Sep 2016
Posts: 2
GMAT ToolKit User
Re: How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 04 Dec 2016, 08:18
SW4 wrote:
How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?

A) 12
B) 11
C) 10
D) 9
E) 8


Thanks to user Bunuel, unforunately first post so cannot link, but formula copied below:
\(\frac{n}{5^k}\), where k must be chosen such that 5^(k+1)>n

For number of zeroes denominator must be less than 43, therefore use:
-> 5 as 5 < 43
-> 5^2 as 25 < 43
-> 5^3 cannot as 125 >43

=\(\frac{43}{5} + \frac{43}{5^2}\)
= 8 + 1
=9

Ans D
Board of Directors
User avatar
P
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4220
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User Premium Member
Re: How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 04 Dec 2016, 09:39
SW4 wrote:
How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?

A) 12
B) 11
C) 10
D) 9
E) 8


43/5 = 8
8/5 = 1

Hence, no of zeroes will be 9

Answer will be (D)


_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50623
Re: How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 05 Dec 2016, 00:40
SW4 wrote:
How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?

A) 12
B) 11
C) 10
D) 9
E) 8




Check Trailing Zeros Questions and Power of a number in a factorial questions in our Special Questions Directory.

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

Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 4170
Location: United States (CA)
Re: How many consecutive zeros will appear at the end of 43! if that numbe  [#permalink]

Show Tags

New post 14 Sep 2018, 16:42
SW4 wrote:
How many consecutive zeros will appear at the end of 43! if that number is expanded out to its final result?

A) 12
B) 11
C) 10
D) 9
E) 8


To determine the number of trailing zeros in a number, we need to determine the number of 5- and-2 pairs within the prime factorization of that number. Each 5-and-2 pair creates a 10, and each 10 creates an additional zero.

Since we know there are fewer 5s in 43! than 2s, we can find the number of 5s and thus be able to determine the number of 5-and-2 pairs.

To determine the number of 5s within 43!, we can use the following shortcut in which we divide 43 by 5, then divide the quotient of 43/5 by 5 and continue this process until we no longer get a nonzero quotient.

43/5 = 8 (we can ignore the remainder)

8/5 = 1 (we can ignore the remainder)

Since 1/5 does not produce a nonzero quotient, we can stop.

The final step is to add up our quotients; that sum represents the number of factors of 5 within 43!.

Thus, there are 8 + 1 = 9 factors of 5 within 43! This means we have nine 5-and-2 pairs, so there are 9 consecutive zeros at the end of 43! when it is expanded to its final result.

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: How many consecutive zeros will appear at the end of 43! if that numbe &nbs [#permalink] 14 Sep 2018, 16:42
Display posts from previous: Sort by

How many consecutive zeros will appear at the end of 43! if that numbe

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


Copyright

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®.