NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 01:12 It is currently 25 Apr 2024, 01:12
Decision Tracker
My Rewards
New posts
New comers' posts

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

If n is an integer from 1 to 9. Is n prime?

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92904
Own Kudos [?]: 618874 [4]
Given Kudos: 81588
Send PM
CAT Tests Forum Quiz Mode
If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 05:52
4
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

55% (hard)

Question Stats:

60% (01:53) correct 40% (01:41) wrong based on 129 sessions
Hide Show timer Statistics

Competition Mode Question



If n is an integer from 1 to 9. Is n prime?


(1) 1/n is terminating decimal number

(2) 1/n has at least 3 non zero digits on right of decimal


Are You Up For the Challenge: 700 Level Questions
ShowHide Answer
Official Answer
C
User avatar
G
TestPrepUnlimited
Tutor
Joined: 17 Sep 2014
Posts: 1251
Own Kudos [?]: 938 [2]
Given Kudos: 6
Location: United States
GMAT 1: 780 Q51 V45
GRE 1: Q170 V167
Send PM
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 06:51
2
Kudos
Expert Reply
Analyzing the question:
Given n can be 1, 2, 3 ... 8, 9.
Is n equal to either 2, 3, 5, or 7?

Statement 1:
For a decimal to terminate, we cannot divide by 3 or any prime number greater than 6.
If 1/n is terminating we can choose n = 1, 2, 4, 5, 8. Out of these n = 2 and n = 5 are prime but the rest aren't, so insufficient.

Statement 2:
We can get a decimal that terminates but has 3 or more digits on the right of the decimal point, or simply a decimal that doesn't terminate.
n = 3, 6, 7, 9 are nonterminating.
n = 8 gives 3 digits. Out of these n = 3 and n = 7 are prime but the rest aren't, insufficient.

Combined:
n = 8 is the only common number in both, sufficient.

Ans: C
User avatar
D
exc4libur
SVP
SVP
Joined: 24 Nov 2016
Posts: 1720
Own Kudos [?]: 1344 [1]
Given Kudos: 607
Location: United States
Send PM
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 06:55
1
Kudos
Quote:
If n is an integer from 1 to 9. Is n prime?


(1) 1/n is terminating decimal number

(2) 1/n has at least 3 non zero digits on right of decimal


n=1,2,3,4,5,6,7,8,9

(1) 1/n is terminating decimal number insufic
1/n=terminating; n=1,2,4,5,8

(2) 1/n has at least 3 non zero digits on right of decimal insufic
1/n=0.ABC…; 1/8=0.125, n=8≠prime; 1/3=0.333, n=3=prime

(1 and 2) sufic
1/n=terminating; n=1,2,4,5,8 but n=0.ABC (not=0)
1/1=1, 1/2=0.5, 1/4=0.25, 1/5=0.2
n=8…1/8=terminating=0.125

Ans (C)
User avatar
L
freedom128
Director
Director
Joined: 30 Sep 2017
Posts: 956
Own Kudos [?]: 1256 [1]
Given Kudos: 402
GMAT 1: 720 Q49 V40
GPA: 3.8
Send PM
Reviews Badge
If n is an integer from 1 to 9. Is n prime? [#permalink] New post   Updated on: 08 Jan 2020, 02:20
1
Kudos
1) 1/n is terminating decimal number, where n=1,2,4,5,8. Some eligible n are prime (2,5), others (1,4,8) are not.
NOT SUFFICIENT

2) 1/n has at least 3 non zero digits on right of decimal, where n=3,6,7,8,9. Some eligible n are prime (3,7), others (6,8,9) are not.
NOT SUFFICIENT

1)+2) only n=8 satisfies both statements. thus, n=8 is not a prime.
SUFFICIENT


FINAL ANSWER IS (C)
Thanks for lacktutor for correcting me.

Posted from my mobile device

Originally posted by freedom128 on 07 Jan 2020, 07:18.
Last edited by freedom128 on 08 Jan 2020, 02:20, edited 1 time in total.
User avatar
D
lacktutor
Director
Director
Joined: 25 Jul 2018
Posts: 668
Own Kudos [?]: 1118 [2]
Given Kudos: 69
Send PM
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 16:46
1
Kudos
If n is an integer from 1 to 9. Is n prime?

(Statement1): \(\frac{1}{n}\) is terminating decimal number.
—> if n=2(prime), then \(\frac{1}{2}\)= 0.5 (YES)
—> if n= 8(not prime), then \(\frac{1}{8}\)= 0.125 (NO)
Insufficient

(Statement2): \(\frac{1}{n}\) has at least 3 non zero digits on right of decimal.
—> if n=3(prime), then \(\frac{1}{3}=0.333\)... (yes)
—> if n= 8(not prime), then \(\frac{1}{8}= 0.125\) (NO)
Insufficient

Taken together 1&2,
—> only one value of n satisfies the both statements—>(n=8).
\(\frac{1}{8} = 0.125\), but n is not prime(always)
Sufficient

The answer is C

Posted from my mobile device
User avatar
L
Archit3110
GMAT Club Legend
GMAT Club Legend
Joined: 18 Aug 2017
Status:You learn more from failure than from success.
Posts: 8019
Own Kudos [?]: 4096 [0]
Given Kudos: 242
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1:
545 Q79 V79 DI73
GPA: 4
WE:Marketing (Energy and Utilities)
Send PM
GMAT ToolKit User CAT Tests
If n is an integer from 1 to 9. Is n prime? [#permalink] New post   Updated on: 11 Jan 2020, 01:21
#1
1/n is terminating decimal number

Yes for 2,5 and 4 insufficient
#2

1/n has at least 3 non zero digits on right of decimal
Only possible no is 7 or 8
insufficient
from 1 &2
no has to be 8

IMO C


If n is an integer from 1 to 9. Is n prime?


(1) 1/n is terminating decimal number

(2) 1/n has at least 3 non zero digits on right of decimal

Posted from my mobile device

Originally posted by Archit3110 on 07 Jan 2020, 18:58.
Last edited by Archit3110 on 11 Jan 2020, 01:21, edited 1 time in total.
User avatar
D
QuantMadeEasy
Senior Manager
Senior Manager
Joined: 28 Feb 2014
Posts: 471
Own Kudos [?]: 559 [0]
Given Kudos: 74
Location: India
Concentration: General Management, International Business
GMAT 1: 570 Q49 V20
GPA: 3.97
WE:Engineering (Education)
Send PM
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 21:03
(1) 1/n is terminating decimal number
To get a terminating decimal,n has be either 2 or 5. Sufficient


(2) 1/n has at least 3 non zero digits on right of decimal
possible values of n can be = 3, 6, 7,8. Insufficient

A is correct.
User avatar
L
madgmat2019
Director
Director
Joined: 01 Mar 2019
Posts: 592
Own Kudos [?]: 506 [0]
Given Kudos: 207
Location: India
Concentration: Strategy, Social Entrepreneurship
GMAT 1: 580 Q48 V21
GPA: 4
Send PM
Reviews Badge
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   07 Jan 2020, 21:45
(1) 1/n is terminating decimal number......1/2,1/4,1/5/1/8... Satisfies... but all are not prime...INSUFFICIENT

(2) 1/n has at least 3 non zero digits on right of decimal......1/3,1/7,1/9,1/6.....but all are not prime...INSUFFICIENT

OA:E
User avatar
D
lacktutor
Director
Director
Joined: 25 Jul 2018
Posts: 668
Own Kudos [?]: 1118 [0]
Given Kudos: 69
Send PM
If n is an integer from 1 to 9. Is n prime? [#permalink] New post   08 Jan 2020, 02:15
chondro48 wrote:
1) 1/n is terminating decimal number, where n=1,2,4,5,8. Some eligible n are prime (2,5), others (1,4,8) are not.
NOT SUFFICIENT

2) 1/n has at least 3 non zero digits on right of decimal, where n=3,6,7,8,9. Some eligible n are prime (3,7), others (6,8,9) are not.
NOT SUFFICIENT

1)+2) only n=3 satisfies both statements. thus, n=3 is prime.
SUFFICIENT


FINAL ANSWER IS (C)

Posted from my mobile device


Hi, chondro48

If you combine statement 1&2 together, only n=8 satisfies the both statements, not n=3.
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32662
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: If n is an integer from 1 to 9. Is n prime? [#permalink] New post   20 Jun 2021, 17:16
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.
GMAT Club Bot
gmatclubot
Re: If n is an integer from 1 to 9. Is n prime? [#permalink]
20 Jun 2021, 17:16
Moderator:
Bunuel
Math Expert
92901 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions