Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 May 2015, 22:13

### 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

# Is the product of A and B equal to 1? (1) A B A = A (2) B A

Author Message
TAGS:
Intern
Joined: 25 Aug 2007
Posts: 14
Followers: 0

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

Is the product of A and B equal to 1? (1) A B A = A (2) B A [#permalink]  19 Nov 2007, 19:29
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Is the product of A and B equal to 1?

(1) A B A = A
(2) B A B = B
SVP
Joined: 29 Aug 2007
Posts: 2497
Followers: 57

Kudos [?]: 556 [0], given: 19

Re: DS Question [#permalink]  19 Nov 2007, 20:54
sujitmgmat wrote:
Is the product of A and B equal to 1?

(1) A B A = A
(2) B A B = B

E.
(1) A B A = A
ABA - A = 0
A (AB - 1) = 0
A = 0
AB = 1 but this not possible because if A = 0, AB cannot be 1.

(2) B A B = B

BAB - B = 0
B (AB - 1) = 0
B = 0
AB = 1 again this is also not possible as above.

So E.
Intern
Joined: 25 Aug 2007
Posts: 14
Followers: 0

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

Thanks GMAT TIGER for responding. However, I am difficulty understanding it.

Statement 1 implies that either A = 0 "or" AB=1. From this how can we conclude that AB=1 is not possible?

Similarly Statement 2 implies that either B=0 "or" AB=1.

Therefore, Statement 1 and 2 will imply that AB=1. That is, I think answer should be (C).

But the answer in GMATCLUB Challenge is given as (E).
Director
Joined: 09 Aug 2006
Posts: 766
Followers: 1

Kudos [?]: 69 [0], given: 0

Re: DS Question [#permalink]  19 Nov 2007, 21:38
sujitmgmat wrote:
Is the product of A and B equal to 1?

(1) A B A = A
(2) B A B = B

Does A B A mean A*B*A? Can you clarify? Thanks.
VP
Joined: 08 Jun 2005
Posts: 1147
Followers: 6

Kudos [?]: 128 [0], given: 0

sujitmgmat wrote:
Thanks GMAT TIGER for responding. However, I am difficulty understanding it.

Statement 1 implies that either A = 0 "or" AB=1. From this how can we conclude that AB=1 is not possible?

Similarly Statement 2 implies that either B=0 "or" AB=1.

Therefore, Statement 1 and 2 will imply that AB=1. That is, I think answer should be (C).

But the answer in GMATCLUB Challenge is given as (E).

This is data sufficiency problem - since you have two options for AB (i.e 0 or 1) then you don't have sufficient data to answer the problem.

Assume A=0 B=0 then AB = 0 in option (C) !

SVP
Joined: 28 Dec 2005
Posts: 1583
Followers: 2

Kudos [?]: 88 [0], given: 2

This might be a silly question, but why can we not do this:

ABA=A
(AB)A=A
AB=1

is it because we dont know whether A is positive or negative ?
CEO
Joined: 29 Mar 2007
Posts: 2591
Followers: 16

Kudos [?]: 234 [0], given: 0

Re: DS Question [#permalink]  20 Nov 2007, 18:13
sujitmgmat wrote:
Is the product of A and B equal to 1?

(1) A B A = A
(2) B A B = B

ABA=A can be 0 1

BAB=B can be 0 or 1

Again A could = B and be 0 or 1.

Insuff.

E
Intern
Joined: 11 Jun 2007
Posts: 22
Followers: 0

Kudos [?]: 14 [0], given: 0

KS,
Why can't the answer be C?
Stmt 1: A= 0 or AB =1
Stmt 2: B=0 or BA =1
When we combine both, don't we get AB = 1

I thought when we combine 2 stmts we take common solution.
Here is one example
http://www.gmatclub.com/forum/t55909

Please explain if I am missing something.
thanks.
Manager
Joined: 03 Sep 2006
Posts: 233
Followers: 1

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

Good question!
Thanks everybody. I got this Q wrong initially ...
Similar topics Replies Last post
Similar
Topics:
2 M01-36: Is the product of a and b equal to 1? 5 09 Jun 2012, 07:49
Is the product of A and B equal to 1? 1. ABA = A 2. BAB = B 8 17 Sep 2008, 09:04
Is the product of A and B equal to 1? (1) A B A = A (2) B A 1 20 Nov 2007, 11:15
if AB is not equal to 0, then a^-1 + b^-1 = 1) a+b 2 -(a+b) 12 18 Sep 2007, 09:04
Does the product of A and B equal to 1 ? 1) A*B*A = A 2) 4 23 Sep 2006, 08:26
Display posts from previous: Sort by