Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 18 Jul 2019, 00:03

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

What is the sum of the unique prime factors of 49,400?

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 56272
What is the sum of the unique prime factors of 49,400?  [#permalink]

Show Tags

New post 17 Jan 2018, 00:10
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

69% (02:15) correct 31% (02:21) wrong based on 72 sessions

HideShow timer Statistics


Senior Manager
Senior Manager
User avatar
G
Joined: 17 Oct 2016
Posts: 317
Location: India
Concentration: Operations, Strategy
GPA: 3.73
WE: Design (Real Estate)
GMAT ToolKit User
Re: What is the sum of the unique prime factors of 49,400?  [#permalink]

Show Tags

New post 17 Jan 2018, 00:14
E

Factors are 19,13,2,2,5,2,5

Sum of unique factors = 19+13+2+5=39


Sent from my iPhone using GMAT Club Forum
_________________
Help with kudos if u found the post useful. Thanks
Manager
Manager
avatar
B
Joined: 29 Oct 2015
Posts: 173
Re: What is the sum of the unique prime factors of 49,400?  [#permalink]

Show Tags

New post 14 Mar 2019, 13:19
Unique factors are 2 , 5 , 19 , 13.
Sum is - 2 + 5 + 19 + 13 = 39
Intern
Intern
avatar
B
Joined: 06 Mar 2019
Posts: 6
GMAT ToolKit User
Re: What is the sum of the unique prime factors of 49,400?  [#permalink]

Show Tags

New post 14 Mar 2019, 13:34
Hi,

There's not other option than try to divide by 7, then 11, then 13, to deduce that the last number is divisible by 13.

49400
494 * 100
247 * 2

Try 247 / 7 => doesn't work
Try 247 / 11 => doesn't work
Try 247 / 13 => Gives 19

Thus, 19 * 13 * 2 *(2 * 2 * 5 * 5)

We don't care for exactitude, as soon as we can see 19 and 13, the sum must be 39 (give or take one or multiple factors of 2 or 5)
Target Test Prep Representative
User avatar
D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 6923
Location: United States (CA)
Re: What is the sum of the unique prime factors of 49,400?  [#permalink]

Show Tags

New post 18 Mar 2019, 18:44
Bunuel wrote:
What is the sum of the unique prime factors of 49,400?

A. 7
B. 10
C. 27
D. 30
E. 39


49,400 = 100 x 494

We see that 100 has primes of only 2 and 5. Now we can break down 494:

494 = 2 x 247 = 2 x 13 x 19

So the sum of the unique primes is:

2 + 5 + 13 + 19 = 39

Answer: E
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

GMAT Club Bot
Re: What is the sum of the unique prime factors of 49,400?   [#permalink] 18 Mar 2019, 18:44
Display posts from previous: Sort by

What is the sum of the unique prime factors of 49,400?

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





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