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

It is currently 25 Sep 2018, 10:10

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 m and n are positive integers, what is the units’ digit of

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Board of Directors
User avatar
P
Joined: 01 Sep 2010
Posts: 3405
If m and n are positive integers, what is the units’ digit of  [#permalink]

Show Tags

New post 27 Aug 2018, 11:12
1
Top Contributor
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

80% (00:40) correct 20% (00:53) wrong based on 15 sessions

HideShow timer Statistics

Manager
Manager
avatar
S
Joined: 20 Feb 2015
Posts: 71
Re: If m and n are positive integers, what is the units’ digit of  [#permalink]

Show Tags

New post 27 Aug 2018, 11:57
1
The cyclicity of 7 is 4 , with last digits 7^1=7, 7^2=9, 7^3=3, 7^4=1
now we need to know the value of m+3+4n to determine the units digit of 7^(m+3+4n)
St1) m=7 i.e 7+3+4n=10+4n
If we divide 10+4n by 4(cyclicity no.) it will always yield remainder 2. So the units digit is same as 7^2 =9
Sufficient
St2) n=2 i.e m+3+8= m+11 . If we divide by 4 , we cannot determine the exact remainder , as different values of m will yield different remainders and hence different unit digits.
Not Sufficient

Ans :A
_________________

You miss 100% of the shots you don't take..

KUDOS Please..!!

Director
Director
User avatar
G
Joined: 31 Oct 2013
Posts: 591
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
Re: If m and n are positive integers, what is the units’ digit of  [#permalink]

Show Tags

New post 27 Aug 2018, 12:48
1
carcass wrote:
If m and n are positive integers, what is the units’ digit of \(7^{m+3+4n}\) ?

(1) m=7

(2) n=2



Discussed here bro.

https://gmatclub.com/forum/if-m-and-n-a ... fl=similar
GMAT Club Bot
Re: If m and n are positive integers, what is the units’ digit of &nbs [#permalink] 27 Aug 2018, 12:48
Display posts from previous: Sort by

If m and n are positive integers, what is the units’ digit of

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

Events & Promotions

PREV
NEXT


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®.