It is currently 22 Jun 2017, 14:12

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# What is the units digit of the above expression?

Author Message
Intern
Joined: 18 Nov 2012
Posts: 4
Location: Greece
Concentration: Finance, Accounting
GMAT 1: 650 Q45 V34
What is the units digit of the above expression? [#permalink]

### Show Tags

18 Nov 2012, 04:02
(2^18)*(3^17)*(7^14)*(5^20)

What is the units digit of the above expression?

A. 0
B. 2
C. 5
D. 7
E. 9

Last edited by Bunuel on 18 Nov 2012, 04:31, edited 1 time in total.
Renamed the topic and edited the question.
VP
Status: Been a long time guys...
Joined: 03 Feb 2011
Posts: 1382
Location: United States (NY)
Concentration: Finance, Marketing
GPA: 3.75
Re: What is the units digit of the above expression? [#permalink]

### Show Tags

18 Nov 2012, 07:42
1
KUDOS
stef91 wrote:
(2^18)*(3^17)*(7^14)*(5^20)

What is the units digit of the above expression?

A. 0
B. 2
C. 5
D. 7
E. 9

cyclicity of 2 is 4
cyclicity of 3 is 4
cyclicity of 7 is 4
cyclicity of 5 is 1.
So divide the respective powers by the integer's own cyclicity.
So the above expression can be written as:
$$2^2 * 3^3 * 7^2 * 5$$
It becomes $$4*27*49*5$$
Since 4*5=20,
so any number, if multiplied by 0 will yield 0 as the last digit.

Hence A.
_________________
Re: What is the units digit of the above expression?   [#permalink] 18 Nov 2012, 07:42
Similar topics Replies Last post
Similar
Topics:
3 If set S consists of positive two-digit integers (m25#32) 6 14 Jun 2012, 03:56
If N is a two-digit positive integer, what is the value of 2 12 Jul 2013, 01:38
25 Which expression is the greatest (m07q16) 15 10 Apr 2013, 07:08
110 What is the last digit 3^{3^3} ? A. 1 B. 3 C. 6 D. 7 E. 9 69 23 Jul 2013, 13:09
14 Counting digits (m09q17) 38 14 Oct 2012, 08:50
Display posts from previous: Sort by

# What is the units digit of the above expression?

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO 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®.