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

It is currently 19 Oct 2019, 16:09

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

Find the number of zeroes in 1142! × 348! × 17!

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

Hide Tags

Find Similar Topics 
Current Student
avatar
V
Joined: 28 May 2014
Posts: 515
GMAT 1: 730 Q49 V41
GMAT ToolKit User
Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

Show Tags

New post Updated on: 27 Jan 2017, 03:53
6
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

52% (02:18) correct 48% (03:00) wrong based on 93 sessions

HideShow timer Statistics

Find the number of zeroes in 1142! × 348! × 17!.

(A) 369
(B) 370
(C) 371
(D) 375
(E) 385

_________________

Originally posted by saswata4s on 27 Jan 2017, 02:22.
Last edited by saswata4s on 27 Jan 2017, 03:53, edited 3 times in total.
Math Expert
avatar
V
Joined: 02 Aug 2009
Posts: 7984
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

Show Tags

New post 27 Jan 2017, 03:12
2
1
saswata4s wrote:
Find the number of zeroes in 1142! × 348! × 17!.

(A) 369
(B) 371
(C) 375
(D) 370
(E) 385


Hi,
Number of 0s will depend upon number of 5s..
1) number of 5s= \(\frac{1142}{5}+\frac{348}{5}+\frac{17}{5}\)=228+69+3=300..
2) number of 25s=\(\frac{1142}{25}+\frac{348}{25}+\frac{17}{25}\)=45+13=58..
3) number of 125s=\(\frac{1142}{125}+\frac{348}{125}+\frac{17}{125}\)=9+2=11..
4) number of 625s=\(\frac{1142}{625}+\frac{348}{625}+\frac{17}{625}\)=1..

Total number of 5s= 300+58+11+1=370

Ans 370..

It seems you have not put the choices in order and that is why 370 is in D choice and not B..
_________________
Current Student
avatar
V
Joined: 28 May 2014
Posts: 515
GMAT 1: 730 Q49 V41
GMAT ToolKit User
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

Show Tags

New post 27 Jan 2017, 03:55
chetan2u wrote:
It seems you have not put the choices in order and that is why 370 is in D choice and not B..


I've updated the correct OA. Thanks for pointing out.

Cheers.
_________________
Director
Director
User avatar
G
Affiliations: CrackVerbal
Joined: 03 Oct 2013
Posts: 563
Location: India
GMAT 1: 780 Q51 V46
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

Show Tags

New post 27 Jan 2017, 03:57
2
Top Contributor
2
Hi sawata4s,
To find the number of zero’s in a factorial, we get to understand, “how we get tens (zero’s) in a factorial?”
We get 10 when we have a minimum of one “2” and one “5”,
10 = 2 * 5
2’s and 5’s in a combination will give us the number of 10’s,
For every “2” in a factorial we may not have a “5”, but for every “5” in a factorial we will have “2”,
So we can just find the number of five’s to evaluate the number of zero’s
There are multiple ways to do that,
you can see the below image for solving it,
So the answer is B.
Hope this helps
Attachments

factorial.png
factorial.png [ 10.04 KiB | Viewed 2749 times ]


_________________
- CrackVerbal Prep Team

For more info on GMAT and MBA, follow us on @AskCrackVerbal

Register for the Free GMAT Kickstarter Course : http://bit.ly/2DDHKHq

Register for our Personal Tutoring Course : https://www.crackverbal.com/gmat/personal-tutoring/

Join the free 4 part GMAT video training series : http://bit.ly/2DGm8tR
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13275
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

Show Tags

New post 20 Aug 2019, 00:29
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 Club Bot
Re: Find the number of zeroes in 1142! × 348! × 17!   [#permalink] 20 Aug 2019, 00:29
Display posts from previous: Sort by

Find the number of zeroes in 1142! × 348! × 17!

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne