GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 26 Jan 2020, 08:35

### 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

# If a and b are positive integers, which of the following

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 21 Oct 2013
Posts: 408
If a and b are positive integers, which of the following  [#permalink]

### Show Tags

30 Jun 2014, 14:36
3
7
00:00

Difficulty:

35% (medium)

Question Stats:

69% (01:38) correct 31% (01:43) wrong based on 240 sessions

### HideShow timer Statistics

If a and b are positive integers, which of the following cannot be an integer?

A. (2b)/(4a+1)
B. (2b)/(3a+1)
C. (2a+1)/(4b)
D. (2a+1)/(4b+1)
E. (2a·b)/(4b+2)
Math Expert
Joined: 02 Sep 2009
Posts: 60646
Re: If a and b are positive integers, which of the following  [#permalink]

### Show Tags

30 Jun 2014, 14:45
3
8
goodyear2013 wrote:
If a and b are positive integers, which of the following cannot be an integer?

A) (2b)/(4a+1)
B) (2b)/(3a+1)
C) (2a+1)/(4b)
D) (2a+1)/(4b+1)
E) (2a·b)/(4b+2)

I'd first look for an option which gives odd/even for any values of a and b, because odd/even is not an integer.

Option C fits: $$\frac{2a+1}{4b}=\frac{even+odd}{even}=\frac{odd}{even}\neq{integer}$$.

To discard other A consider a=5 and b=1.
To discard other B consider a=2 and b=1.
To discard other D consider a=2 and b=1.
To discard other E consider a=3 and b=1.
_________________
##### General Discussion
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1723
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If a and b are positive integers, which of the following  [#permalink]

### Show Tags

02 Jul 2014, 03:00
$$Answer = C = \frac{2a+1}{4b}$$

Adding 1 to a multiple of 2 would always make the resultant an odd number; which is not divisible by 4
Manager
Joined: 07 Dec 2009
Posts: 84
GMAT Date: 12-03-2014
Re: If a and b are positive integers, which of the following  [#permalink]

### Show Tags

29 Nov 2014, 07:40
Can any one explain why not option A ?
(2b)/(4a+1)

If b = 1 and a = 5 ===> 2/21
Senior Manager
Joined: 13 Jun 2013
Posts: 253
Re: If a and b are positive integers, which of the following  [#permalink]

### Show Tags

29 Nov 2014, 08:53
bhatiavai wrote:
Can any one explain why not option A ?
(2b)/(4a+1)

If b = 1 and a = 5 ===> 2/21

hi, please reverse the values, put a=1 and b=5

10/5 = 2
Non-Human User
Joined: 09 Sep 2013
Posts: 14016
Re: If a and b are positive integers, which of the following  [#permalink]

### Show Tags

05 Sep 2018, 21:08
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.
_________________
Re: If a and b are positive integers, which of the following   [#permalink] 05 Sep 2018, 21:08
Display posts from previous: Sort by