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

It is currently 18 Jun 2019, 06:00

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

What is the units digit of (16^8)(44^x)(37^5)?

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

Hide Tags

 
Manager
Manager
avatar
G
Joined: 07 Jun 2018
Posts: 52
Location: United States
What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 25 Oct 2018, 12:51
1
1
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

60% (01:16) correct 40% (01:22) wrong based on 96 sessions

HideShow timer Statistics

What is the units digit of \((16^{8})(44^{x})(37^{5})\)?

(1) x=2y where y is a positive integer.
(2) y=2
RC Moderator
User avatar
V
Joined: 24 Aug 2016
Posts: 804
Location: Canada
Concentration: Entrepreneurship, Operations
GMAT 1: 630 Q48 V28
GMAT 2: 540 Q49 V16
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
Re: What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 25 Oct 2018, 12:58
The query is basically banks on cyclicity 4.
Cyclicity of 4 is 2. for all even cycles the value is 6 and for all odds the value is 4.

(1) sufficient ...... as by defn x is even
(2) not-sufficient ...... no info for x.
Ans A.
_________________
Please let me know if I am going in wrong direction.
Thanks in appreciation.
Director
Director
avatar
G
Joined: 19 Oct 2013
Posts: 525
Location: Kuwait
GPA: 3.2
WE: Engineering (Real Estate)
GMAT ToolKit User
Re: What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 25 Oct 2018, 15:45
Jazzmin wrote:
What is the units digit of \((16^{8})(44^{x})(37^{5})\)?

(1) x=2y where y is a positive integer.
(2) y=2


6 to any positive integer power will have a units digit of 6

5 to any positive integer power will have a units digit of 5.

4 has cycles of 4,6,4,6

Regardles so of the value of y we know the power will be even meaning it is a unit of 6.

We have a unique answer.

Answer choice A

Statement 2) is not in any means needed to find the answer

Posted from my mobile device
Intern
Intern
User avatar
S
Joined: 17 Apr 2018
Posts: 21
Location: Italy
Concentration: General Management, Entrepreneurship
GPA: 3.75
GMAT ToolKit User Premium Member
Re: What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 25 Oct 2018, 23:35
1
Jazzmin wrote:
What is the units digit of \((16^{8})(44^{x})(37^{5})\)?

(1) x=2y where y is a positive integer.
(2) y=2

Time needed: 1 min 20s

To answer, we need to know the units digit of \(44^x\).
Note that powers of 4 elevated to an integer can take 2 values: 4 if the exponent is odd, 6 if the exponent is even. Thus, we just need to know if x is even or odd.

Process of elimination:
1) We know x is gonna be a positive, even number. Sufficient. Eliminate C,E
2) Doesn't provide any useful information. Insufficient. Eliminate B,D.

Correct answer: A
_________________
Give kudos if you found this post helpful :D

My GMAT history:
1st GMATPrep: 620 (Q46, V29)
2nd GMATPrep: 700(Q46, V40)
3rd GMATPrep: 720(Q49, V38)
CEO
CEO
User avatar
P
Joined: 18 Aug 2017
Posts: 3879
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member CAT Tests
Re: What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 16 Apr 2019, 19:19
Jazzmin wrote:
What is the units digit of \((16^{8})(44^{x})(37^{5})\)?

(1) x=2y where y is a positive integer.
(2) y=2



\((16^{8})(44^{x})(37^{5})\)

for 16^8 = 6 always
37^5= 7
for 44^x
x=even = 6 and x odd= 4
#1
x=2y where y is a positive integer.
x will always be even
so 44^x= 4 always
sufficient

#2
no info about x
insufficient
IMO A
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.
Manager
Manager
User avatar
G
Joined: 15 Mar 2014
Posts: 140
Location: Singapore
Concentration: Technology, General Management
Schools: Ross '22
GPA: 3.5
WE: Operations (Telecommunications)
Re: What is the units digit of (16^8)(44^x)(37^5)?  [#permalink]

Show Tags

New post 16 Apr 2019, 19:53
Time taken: 31 sec

a) For x=2y
We know that the power is going to be even. We can find out that even power of 4 will give units digit of 4.
With this, we can find the units digit of the entire question, we CAN but don't HAVE TO.
That is all we need to know since this is DS. Hence, the statement is sufficient.

b) y=2
Statement is insufficient.

Hence, the answer is A.
_________________
Hit +1 Kudos If you like my post! :)
GMAT Club Bot
Re: What is the units digit of (16^8)(44^x)(37^5)?   [#permalink] 16 Apr 2019, 19:53
Display posts from previous: Sort by

What is the units digit of (16^8)(44^x)(37^5)?

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


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