Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 24 May 2017, 12:06

### 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

Author Message
TAGS:

### Hide Tags

Director
Joined: 17 Oct 2005
Posts: 929
Followers: 1

Kudos [?]: 222 [0], given: 0

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

### Show Tags

30 Nov 2005, 10:51
3
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

65% (01:39) correct 35% (00:42) wrong based on 133 sessions

### HideShow timer Statistics

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

$$1) \hspace{4} \frac{a}{b} = \frac{5}{8}$$

2) the greatest common divisor of a and b is 1
[Reveal] Spoiler: OA

Last edited by fluke on 19 Jul 2011, 07:53, edited 1 time in total.
Corrected the question
Manager
Status: I will not stop until i realise my goal which is my dream too
Joined: 25 Feb 2010
Posts: 229
Schools: Johnson '15
Followers: 2

Kudos [?]: 53 [1] , given: 16

### Show Tags

21 Jul 2011, 07:18
1
KUDOS
at miweekend...

consider
a/b=5/8
if u consider some other number 25/40 and simplifying it would also get 5/8 so the value given might not ration not the original value
_________________

Regards,
Harsha

Note: Give me kudos if my approach is right , else help me understand where i am missing.. I want to bell the GMAT Cat

Satyameva Jayate - Truth alone triumphs

SVP
Joined: 24 Sep 2005
Posts: 1885
Followers: 22

Kudos [?]: 322 [0], given: 0

### Show Tags

30 Nov 2005, 11:28
joemama142000 wrote:
If a and b are positive integers, what is the value of a + b?

1) a/b = 5/b

2) the greatest comon divisor of a and b is 1

since a and b are positive integers----> they're not 0
1. ---->a=5 , how about b? -->insuff
2. 3 and 5, 5 and 7, yields different sums ----->insuff

1 and 2. a=5, b can be 3 or 7 or 2, etc.....------>insuff

E
Director
Joined: 17 Oct 2005
Posts: 929
Followers: 1

Kudos [?]: 222 [0], given: 0

### Show Tags

30 Nov 2005, 12:15
Here is my explanation:

1) insuff, dont know what a or b are 8a=5b

2)insuff, this is saying that greatest common factor of a and b is 1
ex. 12 and 7 or any prime number pair ( ex. 2 and 5)

together

5/8= a/b : answers have to be multiples of the numberator and denominator. ex. 10 and 16 or 15 and 24. These answers have common factors. Since 5 and 8 are in its most simplified fraction form, it has to be the answer.

If you can explain it better please let us know. thanks
SVP
Joined: 05 Apr 2005
Posts: 1712
Followers: 5

Kudos [?]: 79 [0], given: 0

### Show Tags

30 Nov 2005, 18:21
joemama142000 wrote:
If a and b are positive integers, what is the value of a + b?
1) a/b = 5/b
2) the greatest comon divisor of a and b is 1

joemama142000 wrote:
Here is my explanation:
1) insuff, dont know what a or b are 8a=5b
2)insuff, this is saying that greatest common factor of a and b is 1
ex. 12 and 7 or any prime number pair ( ex. 2 and 5)
together
5/8= a/b: answers have to be multiples of the numberator and denominator. ex. 10 and 16 or 15 and 24. These answers have common factors. Since 5 and 8 are in its most simplified fraction form, it has to be the answer.
If you can explain it better please let us know. thanks
Director
Joined: 17 Oct 2005
Posts: 929
Followers: 1

Kudos [?]: 222 [0], given: 0

### Show Tags

30 Nov 2005, 18:28
sorry all, my mistake. must have been really tired today. In that case you are correct and the answer is E
Director
Joined: 17 Oct 2005
Posts: 929
Followers: 1

Kudos [?]: 222 [0], given: 0

### Show Tags

30 Nov 2005, 18:34
Anyway, here is the original question and explanation. I thought it was tricky.

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.

Here is my explanation:

1) insuff, dont know what a or b are 8a=5b

2)insuff, this is saying that greatest common factor of a and b is 1
ex. 12 and 7 or any prime number pair ( ex. 2 and 5)

together

5/8= a/b : answers have to be multiples of the numberator and denominator. ex. 10 and 16 or 15 and 24. These answers have common factors. Since 5 and 8 are in its most simplified fraction form, it has to be the answer.
Intern
Joined: 29 Jun 2011
Posts: 36
Followers: 0

Kudos [?]: 5 [0], given: 0

### Show Tags

19 Jul 2011, 06:46
joemama142000 wrote:
Anyway, here is the original question and explanation. I thought it was tricky.

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.

Here is my explanation:

1) insuff, dont know what a or b are 8a=5b

2)insuff, this is saying that greatest common factor of a and b is 1
ex. 12 and 7 or any prime number pair ( ex. 2 and 5)

together

5/8= a/b : answers have to be multiples of the numberator and denominator. ex. 10 and 16 or 15 and 24. These answers have common factors. Since 5 and 8 are in its most simplified fraction form, it has to be the answer.

SORRY! if i'm asking a silly question...

since a/b = 5/8. why can't we just plug in a = 5 and b = 8? Pls explain. thanks!
Senior Manager
Joined: 11 Apr 2011
Posts: 266
Followers: 32

Kudos [?]: 507 [0], given: 13

### Show Tags

19 Jul 2011, 21:22
Damn i thought it was C!
_________________

Powerscore CR Bible Full Chapter Notes | Easily Extend Vocabulary List with Google Dictionary

Please kudo me if you found my post useful. Thanks!!!

Intern
Joined: 29 Jun 2011
Posts: 36
Followers: 0

Kudos [?]: 5 [0], given: 0

### Show Tags

22 Jul 2011, 01:33
miweekend wrote:
joemama142000 wrote:
Anyway, here is the original question and explanation. I thought it was tricky.

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.

Here is my explanation:

1) insuff, dont know what a or b are 8a=5b

2)insuff, this is saying that greatest common factor of a and b is 1
ex. 12 and 7 or any prime number pair ( ex. 2 and 5)

together

5/8= a/b : answers have to be multiples of the numberator and denominator. ex. 10 and 16 or 15 and 24. These answers have common factors. Since 5 and 8 are in its most simplified fraction form, it has to be the answer.

SORRY! if i'm asking a silly question...

since a/b = 5/8. why can't we just plug in a = 5 and b = 8? Pls explain. thanks!

thanks. good explanation indeed. never think of it...
Re: Re:   [#permalink] 22 Jul 2011, 01:33
Similar topics Replies Last post
Similar
Topics:
5 What is the value of positive integer b? 4 08 Feb 2017, 06:48
1 If a and b are positive integers, then what is the value of a^b? 1 05 Oct 2016, 01:29
5 If a, b and c are positive integers, what is the value of 10 16 Mar 2017, 07:08
37 If a is positive, what is the value of b? 8 18 Aug 2016, 07:35
6 If a and b are positive integers, what is the value of a + b 5 30 Apr 2015, 09:58
Display posts from previous: Sort by