Last visit was: 15 Dec 2024, 05:45 It is currently 15 Dec 2024, 05:45
Home
GMAT
Messages
Tests
Schools
Reviews
Social
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
CAMANISHPARMAR
User avatar
Joined: 12 Feb 2015
Last visit: 13 Mar 2022
Posts: 1,038
Own Kudos:
2,247
 []
Given Kudos: 77
Posts: 1,038
Kudos: 2,247
 []
How many zeros does 250! end with? 03 Jul 2018, 04:04
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

86% (00:56) correct 14% (01:12) wrong based on 102 sessions

History

Date
Time
Result
Not Attempted Yet
How many zeros does 250! end with?

A. 60
B. 62
C. 64
D. 68
E. 70
ShowHide Answer
Official Answer
B
User avatar
chetan2u
User avatar
RC & DI Moderator
Joined: 02 Aug 2009
Last visit: 14 Dec 2024
Posts: 11,433
Own Kudos:
38,058
Given Kudos: 333
Status:Math and DI Expert
Products:
My Reviews
Expert reply
Posts: 11,433
Kudos: 38,058
How many zeros does 250! end with? 03 Jul 2018, 05:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
CAMANISHPARMAR
How many zeros does 250! end with?

A. 60
B. 62
C. 64
D. 68
E. 70

Numerous question on the subject..
ans wr would depend on the number of times 5 comes in 1*2*3*...*250

it is \(\frac{250}{5}+\frac{250}{5^2}+\frac{250}{5^3}=50+10+2=62\)
beyond 250/5^3 it will become<1, so discard

B
User avatar
Hero8888
User avatar
Joined: 29 Dec 2017
Last visit: 14 Apr 2019
Posts: 301
Own Kudos:
322
 []
Given Kudos: 273
Location: United States
Concentration: Marketing, Technology
GMAT 1: 630 Q44 V33
GMAT 2: 690 Q47 V37
GMAT 3: 710 Q50 V37
GPA: 3.25
WE:Marketing (Telecommunications)
GMAT 3: 710 Q50 V37
Posts: 301
Kudos: 322
 []
How many zeros does 250! end with? 03 Jul 2018, 05:43
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
To calculate zeros in any n! we have to check how many "5" it has

250/5=50
250/5^2=10
250/5^3=2

50+10+2=62

Answer B. 62
User avatar
Abhishek009
User avatar
Board of Directors
Joined: 11 Jun 2011
Last visit: 02 Oct 2024
Posts: 6,014
Own Kudos:
4,952
Given Kudos: 463
Status:QA & VA Forum Moderator
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Posts: 6,014
Kudos: 4,952
How many zeros does 250! end with? 03 Jul 2018, 08:28
Kudos
Add Kudos
Bookmarks
Bookmark this Post
CAMANISHPARMAR
How many zeros does 250! end with?

A. 60
B. 62
C. 64
D. 68
E. 70
\(\frac{250}{5} = 50\)
\(\frac{50}{5} = 10\)
\(\frac{10}{5} = 2\)

So, 250! must end in 62 zeroes, answer must be (B)
avatar
emidra
avatar
Current Student
Joined: 26 Jan 2020
Last visit: 21 Apr 2021
Posts: 3
Own Kudos:
10
Given Kudos: 21
Posts: 3
Kudos: 10
How many zeros does 250! end with? 30 Jan 2020, 19:42
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello,

Can somebody help me understand why we are searching for the number of "5's" in 250!? I had taken a similar approach but was looking for the numbers which were factors of 10 (250,245,242...) and arrived at 50 "10's". What is the reason for adding the factors 250/5^2 and 250/5^3?

Thank you!!!

Posted from my mobile device
User avatar
fauji
User avatar
IIM School Moderator
Joined: 05 Jan 2015
Last visit: 15 Jun 2021
Posts: 385
Own Kudos:
386
Given Kudos: 214
Status:So far only Dreams i have!!
WE:Consulting (Computer Software)
Products:
My Reviews
Posts: 385
Kudos: 386
How many zeros does 250! end with? 30 Jan 2020, 19:56
Kudos
Add Kudos
Bookmarks
Bookmark this Post
vlfalk
Hello,

Can somebody help me understand why we are searching for the number of "5's" in 250!? I had taken a similar approach but was looking for the numbers which were factors of 10 (250,245,242...) and arrived at 50 "10's". What is the reason for adding the factors 250/5^2 and 250/5^3?

Thank you!!!

Posted from my mobile device

Hi,

To count number of trailing zeroes, we actually check the divisibility by 10. Since 10 has prime factors 5 and 2, on checking for factors of 5 in 250!, equal number of factors of 2 are also counted.

For more understanding on this concept, refer to GC Math book.
https://gmatclub.com/forum/gmat-math-bo ... 30609.html
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 35,827
Own Kudos:
930
Posts: 35,827
Kudos: 930
How many zeros does 250! end with? 02 Aug 2022, 18:49
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderator:
Bunuel
Math Expert
97883 posts