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

 It is currently 14 Oct 2019, 01:12 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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}

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

Hide Tags

Senior PS Moderator V
Joined: 26 Feb 2016
Posts: 3337
Location: India
GPA: 3.12
What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}  [#permalink]

Show Tags 00:00

Difficulty:   45% (medium)

Question Stats: 63% (01:52) correct 38% (02:15) wrong based on 45 sessions

HideShow timer Statistics

What is the unit's digit in the numerical value of $$(2)^{37} * (3)^{47} * (7)^{79} * (13)^{26}$$?

A. 2
B. 4
C. 6
D. 8
E. 9

Source: Experts Global

_________________
You've got what it takes, but it will take everything you've got
Senior Manager  D
Joined: 18 Jun 2018
Posts: 263
What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}  [#permalink]

Show Tags

pushpitkc wrote:
What is the unit's digit in the numerical value of $$(2)^{37} * (3)^{47} * (7)^{79} * (13)^{26}$$?

A. 2
B. 4
C. 6
D. 8
E. 9

Source: Experts Global

OA:D

2,3,7 have cyclicity of 4
Unit digit of $$2^{37} =2$$
Unit digit of $$3^{47}= 7$$
Unit digit of$$7^{79} =3$$
Unit digit of $$13^{26} =9$$
Unit digit of $$2*7*3*9= 8$$
VP  D
Status: Learning stage
Joined: 01 Oct 2017
Posts: 1019
WE: Supply Chain Management (Energy and Utilities)
Re: What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}  [#permalink]

Show Tags

pushpitkc wrote:
What is the unit's digit in the numerical value of $$(2)^{37} * (3)^{47} * (7)^{79} * (13)^{26}$$?

A. 2
B. 4
C. 6
D. 8
E. 9

Source: Experts Global

Cyclicity of 2,3, and 7 is 4
Cyclicity of 13: 3-9-7-1-3-9-7-1-3

So, unit's digit in the numerical value of $$(2)^{37} * (3)^{47} * (7)^{79} * (13)^{26}$$=2*7*3*9=378

Ans. (D)
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
Board of Directors D
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4753
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
Re: What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}  [#permalink]

Show Tags

pushpitkc wrote:
What is the unit's digit in the numerical value of $$(2)^{37} * (3)^{47} * (7)^{79} * (13)^{26}$$?

A. 2
B. 4
C. 6
D. 8
E. 9

Source: Experts Global

$$(2)^{37} = (2)^{4*9+1}$$ = Units Digit $$2$$ ; As $$2^4 = 6$$ and $$2^1 = 2$$

$$(3)^{47} = (3)^{4*11+3}$$ = Units Digit $$7$$ ; As $$3^4 = 1$$ and $$3^3 = 7$$

$$(7)^{79} = (7)^{4*19 + 3}$$ = Units Digit $$3$$ ; As $$7^4 = 1$$ and $$7^3 = 3$$

(13)^{26} = (13)^{4*6 +2 } = Units Digit $$9$$ ; As $$3^4 = 1$$ and $$3^2 = 9$$

Thus, the units digit is $$2*7*3*9 = xx8$$, Answer must be (D)
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only ) Re: What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}   [#permalink] 09 Aug 2018, 09:02
Display posts from previous: Sort by

What is the unit's digit in the numerical value of (2)^{37} * (3)^{47}

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

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