It is currently 13 Dec 2017, 05:21

# Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1

### 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

# If a and b are positive integers, what is the value of a + b

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

### Hide Tags

VP
Joined: 03 Apr 2007
Posts: 1339

Kudos [?]: 876 [0], given: 10

If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

16 May 2008, 15:59
3
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

72% (00:38) correct 28% (01:00) wrong based on 113 sessions

### HideShow timer Statistics

If a and b are positive integers, what is the value of a + b?

(1) $$\frac{a}{b} = \frac{5}{8}$$
(2) The greatest common divisor of a and b is 1.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-a-and-b-are-positive-itegers-what-is-the-value-of-a-b-135199.html
[Reveal] Spoiler: OA

Kudos [?]: 876 [0], given: 10

Director
Joined: 23 Sep 2007
Posts: 782

Kudos [?]: 254 [0], given: 0

Re: If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

16 May 2008, 16:21
goalsnr wrote:
If a and b are positive integers, what is the value of a + b ?
(1) a/b=5/8
(2) The greatest common divisor of a and b is 1

statement 1 is not suff

statement 2 is not suff, but it says that a & b are not divisible by each other.

C

Kudos [?]: 254 [0], given: 0

Manager
Joined: 16 Sep 2007
Posts: 215

Kudos [?]: 12 [1], given: 0

Re: If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

16 May 2008, 16:23
1
KUDOS
1)
let a=5
let b=8

let a=10
let b=16

insufficient

2)
insufficient

1&2)
a and b must maintain the same ratio.

5*x/(8*x). The only value of x that will satisfy 2 is x=1. Therefore, a+b=5+8=13.
sufficient

C

Kudos [?]: 12 [1], given: 0

Senior Manager
Joined: 19 Apr 2008
Posts: 313

Kudos [?]: 99 [1], given: 0

Re: If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

16 May 2008, 16:26
1
KUDOS
goalsnr wrote:
If a and b are positive integers, what is the value of a + b ?
(1) a/b=5/8
(2) The greatest common divisor of a and b is 1

C ?

1) a/b =5/8

a=5 ; b=8; a/b =5/8 ; a+b =13
a=10 ;b=16 ;a/b =5/8 ;a+b=26

insuff

2) insuff ...no information about values of a and b .

Together sufficient: if GCD of a and b is 1 , only possible values of a and b are 5 and 8 respectively, so a+b=13

Kudos [?]: 99 [1], given: 0

Non-Human User
Joined: 09 Sep 2013
Posts: 14878

Kudos [?]: 287 [0], given: 0

Re: If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

30 Apr 2015, 08:04
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.
_________________

Kudos [?]: 287 [0], given: 0

Math Expert
Joined: 02 Sep 2009
Posts: 42578

Kudos [?]: 135467 [0], given: 12695

Re: If a and b are positive integers, what is the value of a + b [#permalink]

### Show Tags

30 Apr 2015, 08:58
Expert's post
2
This post was
BOOKMARKED
If a and b are positive integers, what is the value of a + b?

(1) $$\frac{a}{b} = \frac{5}{8}$$ --> $$a$$ and $$b$$ could be: (5, 8), (10, 16), (15, 24), ... Not sufficient.

(2) The greatest common divisor of a and b is 1. Clearly insufficient: $$a$$ and $$b$$ could be any co-prime numbers.

(1)+(2) Since from (2) $$a$$ and $$b$$ do not share any common factor but 1, then from (1) $$a=5$$ and $$b=8$$ --> $$a+b=13$$. Sufficient.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-a-and-b-are-positive-itegers-what-is-the-value-of-a-b-135199.html
_________________

Kudos [?]: 135467 [0], given: 12695

Re: If a and b are positive integers, what is the value of a + b   [#permalink] 30 Apr 2015, 08:58
Display posts from previous: Sort by

# If a and b are positive integers, what is the value of a + b

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.