If a, b, and c are positive distinct integers, is (a/b)/c an

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 14 Apr 2010

Posts: 241

Followers: 2

Kudos [?]: 8 [0], given: 1

If a, b, and c are positive distinct integers, is (a/b)/c an [#permalink]

13 Jul 2010, 09:48

00:00

Question Stats:

47% (01:59) correct

52% (00:59) wrong

based on 21 sessions

If a, b, and c are positive distinct integers, is (a/b)/c an integer?

(1) c = 2
(2) a = b+c

[Reveal] Spoiler: OA

Last edited by Bunuel on 08 Nov 2012, 03:18, edited 1 time in total.

Edited the question.

Status: The last round

Joined: 18 Jun 2009

Posts: 1325

Concentration: Strategy, General Management

Schools: Stanford '14 (D), Booth '14 (D), Johnson '14 (D)

GMAT 1: 680 Q48 V34

Followers: 44

Kudos [?]: 386 [0], given: 156

Re: m05 [#permalink]

13 Jul 2010, 10:04

A humble request: I think there is a separate section for GMAT Club tests. There you can find the already discussed questions too.

Now coming to the problem.
1 is clearly insufficient.
2 is sufficient. No combination can be found in which (a/b)/c is an integer provided a= b + c & a, b, c are distinct.
_________________

[ From 470 to 680-My Story ] [ My Last Month Before Test ]
[ GMAT Prep Analysis Tool ] [ US. Business School Dashboard ] [ Int. Business School Dashboard ]

I Can, I Will

Find out what's new at GMAT Club - latest features and updates

GMAT Club team member

Joined: 02 Sep 2009

Posts: 12122

Followers: 1879

Kudos [?]: 10139 [2] , given: 970

Re: m05 [#permalink]

13 Jul 2010, 10:29

This post received
KUDOS

bibha wrote:

If a, b, and c are positive distinct integers, is (a/b)/c an integer?
1. c=2
2. a = b+c

First of all \frac{\frac{a}{b}}{c}=\frac{a}{bc}. So the question becomes is \frac{a}{bc}=integer true?

(1) c=2 --> is \frac{a}{2b}=integer. Clearly insufficient. If a=1, then answer is NO, but if a=4 and b=1, then the answer is YES.

(2) a=b+c --> \frac{a}{bc}=\frac{b+c}{bc}=\frac{b}{bc}+\frac{c}{bc}=\frac{1}{c}+\frac{1}{b}. As b and c are distinct integers then \frac{1}{c}+\frac{1}{b} won't be an integer. Sufficient. (Side note: if b and c were not distinct integers then \frac{1}{c}+\frac{1}{b} could be an integer in the following cases: b=c=1 and b=c=2).

Answer: B.

Hope it helps.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!! ,11 Mixed Questions NEW!!!, 12 Fresh Meat NEW!!!

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!, 11 New DS set. NEW!!!

What are GMAT Club Tests?
25 extra-hard Quant Tests

Find out what's new at GMAT Club - latest features and updates

Intern

Joined: 19 May 2009

Posts: 1

Followers: 0

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

Re: If a, b, and c are positive distinct integers, is (a/b)/c an [#permalink]

07 Nov 2012, 20:37

Bunuel,

Stupid question. But....

When I see the question: Is a/bc = Integer. My mind immediately multiplies the equation by bc on both sides and comes up with a new question...

Is a = (integer) (bc)

since both b and c are distinct integers and thus bc will be an integer, the question is asking if a = integer.

If this is accurate, then isn't option B a straightforward Yes? If A = B +C, then A is just an addition of two distinct integers, making A itself an integer, answering the original question.

Can you help point out where I went wrong?

Thanks.

GMAT Club team member

Joined: 02 Sep 2009

Posts: 12122

Followers: 1879

Kudos [?]: 10139 [0], given: 970

Re: If a, b, and c are positive distinct integers, is (a/b)/c an [#permalink]

08 Nov 2012, 03:27

navalpike wrote:

If the question could be rephrased as "is a an integer", then we wouldn't need any statement to answer the question, since the stem directly says that a is an integer.

The question asks whether \frac{a}{bc} is an integer or whether a is a multiple of bc.

Hope it helps.
_________________

Re: If a, b, and c are positive distinct integers, is (a/b)/c an [#permalink] 08 Nov 2012, 03:27

		Similar topics	Author	Replies	Last post
Similar Topics:		a,b and c are positive integers such that abc= 450 and	kevincan	14	18 Sep 2006, 01:42
		If a, b, and c are positive distinct integers, is	neelesh	3	18 Feb 2008, 11:59
		If a, b, and c are positive distinct integers, is a/bc an	Nihit	1	08 Jun 2008, 03:09
		DS_divisibility m05 #36	IrinaOK	7	10 Oct 2007, 00:40
	4	If a,b,c, d are distinct even integers and a is prime, is	enigma123	7	06 Jul 2011, 06:22

If a, b, and c are positive distinct integers, is (a/b)/c an

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

If a, b, and c are positive distinct integers, is (a/b)/c an

If a, b, and c are positive distinct integers, is (a/b)/c an

Main navigation

GMAT Resources

Partners

MBA Resources