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

It is currently 26 Mar 2019, 07:54

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

Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv

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

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 53864
Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv  [#permalink]

Show Tags

New post 05 Mar 2019, 05:21
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

71% (01:29) correct 29% (01:09) wrong based on 34 sessions

HideShow timer Statistics

Intern
Intern
avatar
B
Joined: 19 Jan 2019
Posts: 48
Re: Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv  [#permalink]

Show Tags

New post 05 Mar 2019, 05:32
1
Statement 1 - x = 5b
From this we know that X has atleast one prime factor... But we don't know anything about "b".. not sufficient..

Statement 2 - not sufficient.

Combining both
We know that x = 5b,
And b = 2c.
Therefore x = 5 * 2c
Now we know that x atleast has 2 prime factors i.e 5 &2, but "c" can take any value. For e.g if c = 7, then x will have atleast 3 prime factors.. but if c = 2, then x will not have three prime factors.... Combining both statements is still not sufficient to get to the conclusion... Option E is the right answer...


Am I right??

Posted from my mobile device
Intern
Intern
avatar
B
Joined: 11 Dec 2018
Posts: 10
Re: Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv  [#permalink]

Show Tags

New post 05 Mar 2019, 10:02
IMO C

1) clearly insufficient. For example

if b= 1. ----> x has 2 prime factors 1 and 5;
if b= 3 -----> x has 3 prime factor 1, 3 and 5;

2) claearly insufficient

1 + 2) x= 5*2C = 10c. If we multiply 10 for any positive integer, we always have at list 3 prime factors: 1,2,5

for example

if c= 1 -----> X = 10*1 = 10 in this case x has 3 prime factors 1,2,5
if c=19 -----> X = 190 in this case has at least 3 positive factors 1,2,5

Is my answer right? O someone can give an explanation?
CEO
CEO
User avatar
P
Joined: 18 Aug 2017
Posts: 2502
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member CAT Tests
Re: Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv  [#permalink]

Show Tags

New post 05 Mar 2019, 11:43
Bunuel wrote:
Does x have at least 3 prime factors?

(1) x = 5b, where b is a positive integer.
(2) b = 2c, where c is a positive integer.


#1
x=5b
x=5; no
x=50;no
x=60 ; yes 3 prime factors 2^2*3*5
in sufficient
#2
b=2c
no info of x in sufficeint
from1 &2
@ b= 2-10 ; no 3 prime factors i.e x=50
but @b>12 ; >=3 prime factors i.e x=60 onwards
in sufficient
IMO E
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.
GMAT Club Bot
Re: Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv   [#permalink] 05 Mar 2019, 11:43
Display posts from previous: Sort by

Does x have at least 3 prime factors? (1) x = 5b, where b is a positiv

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


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®.