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

 It is currently 16 Jan 2019, 00:58

### 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

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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### The winning strategy for a high GRE score

January 17, 2019

January 17, 2019

08:00 AM PST

09:00 AM PST

Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
• ### Free GMAT Strategy Webinar

January 19, 2019

January 19, 2019

07:00 AM PST

09:00 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.

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

Author Message
TAGS:

### Hide Tags

Current Student
Joined: 27 May 2014
Posts: 525
GMAT 1: 730 Q49 V41
Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

### Show Tags

Updated on: 27 Jan 2017, 02:53
5
00:00

Difficulty:

85% (hard)

Question Stats:

49% (01:39) correct 51% (02:10) wrong based on 85 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, 01:22.
Last edited by saswata4s on 27 Jan 2017, 02:53, edited 3 times in total.
Math Expert
Joined: 02 Aug 2009
Posts: 7199
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

### Show Tags

27 Jan 2017, 02:12
1
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..
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor

Current Student
Joined: 27 May 2014
Posts: 525
GMAT 1: 730 Q49 V41
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

### Show Tags

27 Jan 2017, 02:55
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
Affiliations: CrackVerbal
Joined: 03 Oct 2013
Posts: 534
Location: India
GMAT 1: 780 Q51 V46
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

### Show Tags

27 Jan 2017, 02:57
1
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,
Hope this helps
Attachments

factorial.png [ 10.04 KiB | Viewed 1743 times ]

_________________

Register for the Free GMAT Video Training Course : https://crackverbal.com/MBA-Through-GMAT-2019-Registration

Non-Human User
Joined: 09 Sep 2013
Posts: 9405
Re: Find the number of zeroes in 1142! × 348! × 17!  [#permalink]

### Show Tags

07 Jan 2019, 10:56
1
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.
_________________
Re: Find the number of zeroes in 1142! × 348! × 17! &nbs [#permalink] 07 Jan 2019, 10:56
Display posts from previous: Sort by