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

It is currently 22 Oct 2018, 05:43

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

Need clarification on finding Prime Factors

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

Hide Tags

Intern
Intern
avatar
B
Joined: 14 Apr 2015
Posts: 28
Location: United States
Concentration: Nonprofit, Entrepreneurship
GMAT Date: 06-14-2015
GPA: 3.93
WE: Marketing (Non-Profit and Government)
Need clarification on finding Prime Factors  [#permalink]

Show Tags

New post 02 May 2015, 14:27
1
Quant is not my strength, so this question may seem a bit silly, but when a question asks "how many prime factors does X have?" In general, does it mean unique prime factors?

For example the prime factors of 48, {(2^4), 3}
If a question asks, how many prime factors does 48 have? Would you answer two, or five? Will a question specifically ask for Unique Prime Factors if that's what it is looking for?
Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1243
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Re: Need clarification on finding Prime Factors  [#permalink]

Show Tags

New post 02 May 2015, 15:36
3
meshackb wrote:
Quant is not my strength, so this question may seem a bit silly, but when a question asks "how many prime factors does X have?" In general, does it mean unique prime factors?

For example the prime factors of 48, {(2^4), 3}
If a question asks, how many prime factors does 48 have? Would you answer two, or five? Will a question specifically ask for Unique Prime Factors if that's what it is looking for?


Hello meshackb
When task asks about prime factors of a number, you only need distinct values.
So 48 has two prime factors: 2 and 3
_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

Intern
Intern
avatar
Joined: 01 Jun 2010
Posts: 38
Re: Need clarification on finding Prime Factors  [#permalink]

Show Tags

New post 12 May 2015, 22:20
Harley1980 wrote:
meshackb wrote:
Quant is not my strength, so this question may seem a bit silly, but when a question asks "how many prime factors does X have?" In general, does it mean unique prime factors?

For example the prime factors of 48, {(2^4), 3}
If a question asks, how many prime factors does 48 have? Would you answer two, or five? Will a question specifically ask for Unique Prime Factors if that's what it is looking for?


Hello meshackb
When task asks about prime factors of a number, you only need distinct values.
So 48 has two prime factors: 2 and 3


Hey Harley1980, can you provide an official example that deals with prime factors, and the official answer only means unique (without stating "unique" or "different" somewhere in the problem)? I was taking a look through MGMAT's Number Properties book (5th ed) and when they talk about counting prime factors they state that the total number of prime factors of 252 is 5 (2,2,3,3,7) (top of pg 96). On the previous page they talk about the different ways that factor questions can be asked, and they explicitly state "different prime factors" or "unique prime factors" when the answer should only be 2,3,7 - for the previous example. There are also some previous examples in the book when they mention prime factors they explicitly state all of the multiplicities.

I'm coming from an academic math background, so my understanding of prime factorization stems from that.
_________________

Please don't forget to give kudos if you found someone's post helpful. Everyone likes kudos! :)

Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1243
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Re: Need clarification on finding Prime Factors  [#permalink]

Show Tags

New post 12 May 2015, 23:43
1
wakk0 wrote:
Harley1980 wrote:
meshackb wrote:
Quant is not my strength, so this question may seem a bit silly, but when a question asks "how many prime factors does X have?" In general, does it mean unique prime factors?

For example the prime factors of 48, {(2^4), 3}
If a question asks, how many prime factors does 48 have? Would you answer two, or five? Will a question specifically ask for Unique Prime Factors if that's what it is looking for?


Hello meshackb
When task asks about prime factors of a number, you only need distinct values.
So 48 has two prime factors: 2 and 3


Hey Harley1980, can you provide an official example that deals with prime factors, and the official answer only means unique (without stating "unique" or "different" somewhere in the problem)? I was taking a look through MGMAT's Number Properties book (5th ed) and when they talk about counting prime factors they state that the total number of prime factors of 252 is 5 (2,2,3,3,7) (top of pg 96). On the previous page they talk about the different ways that factor questions can be asked, and they explicitly state "different prime factors" or "unique prime factors" when the answer should only be 2,3,7 - for the previous example. There are also some previous examples in the book when they mention prime factors they explicitly state all of the multiplicities.

I'm coming from an academic math background, so my understanding of prime factorization stems from that.


Hello wakk0.

Here is example
the-positive-integer-k-has-exactly-two-positive-prime-factor-60634.html
in which task says that number k has exactly two primes. And after we solved task we can see that k = 63 so k = 3 * 3 * 7 and has 3 prime factors with repetions and 2 prime factors without repetions. So we can infer that GMAC count primes without repetions.

But you are absolutely right: this is really uncommon case for official tasks. Usually GMAC questions avoid any ambiguity and clearly specify what we need to seek:

"different prime factors":
how-many-different-prime-numbers-are-factors-of-the-positive-102487.html
if-n-is-the-product-of-the-integers-from-1-to-8-inclusive-50953.html

Or if they want include repetions of primes they mention it as "prime including repetions":
the-prime-sum-of-an-integer-n-greater-than-1-is-the-sum-of-167088.html

and Manhattan example of task in with we should find primes with repetitions "prime factors, not necessarily distinct":
for-any-integer-k-1-the-term-length-of-an-integer-108124.html
_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8523
Premium Member
Re: Need clarification on finding Prime Factors  [#permalink]

Show Tags

New post 29 Jan 2018, 00:05
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

GMAT Club Bot
Re: Need clarification on finding Prime Factors &nbs [#permalink] 29 Jan 2018, 00:05
Display posts from previous: Sort by

Need clarification on finding Prime Factors

  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®.