If (a-1)(b-2) =0, which of the following must be true ? : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 10:48

# STARTING SOON:

Open Admission Chat with MBA Experts of Personal MBA Coach - Join Chat Room to Participate.

### 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-1)(b-2) =0, which of the following must be true ?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 31 Oct 2011
Posts: 324
Followers: 3

Kudos [?]: 890 [0], given: 18

If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

21 Mar 2012, 13:52
5
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

57% (01:39) correct 43% (00:33) wrong based on 202 sessions

### HideShow timer Statistics

If (a-1)(b-2) =0, which of the following must be true ?

I. a=1 and b=2
II. if a is not = 1, then b=2
III. if a=1, then b is not=2

A. I only
B. II only
C. III only
D. I and II
E. II and III
[Reveal] Spoiler: OA

Last edited by Bunuel on 21 Mar 2012, 14:02, edited 1 time in total.
Edited the question
Manager
Joined: 22 Feb 2012
Posts: 93
Schools: HBS '16
GMAT 1: 740 Q49 V42
GMAT 2: 670 Q42 V40
GPA: 3.47
WE: Corporate Finance (Aerospace and Defense)
Followers: 2

Kudos [?]: 23 [0], given: 25

Re: PT #13 PS 4 Q 16 [#permalink]

### Show Tags

21 Mar 2012, 13:57
You need to edit the question sir..

should be:

(a-1)(b-2)=0

The only thing you can say for sure is either a = 1 or b = 2 or both

If A doesnt equal 1, then b must equal 2
Math Expert
Joined: 02 Sep 2009
Posts: 36548
Followers: 7076

Kudos [?]: 93091 [2] , given: 10552

Re: PT #13 PS 4 Q 16 [#permalink]

### Show Tags

21 Mar 2012, 14:01
2
KUDOS
Expert's post
1
This post was
BOOKMARKED
eybrj2 wrote:
If (a - 1) (b - 1) = 0, which of the following must be true?

1. a = 1 and b = 2

2. If a is not 1, then b = 2

3. If a =1, then b is not 2.

a) 1 only

b) 2 only

c) 3 only

d) 1 and 2

e) 2 and 3

If (a-1)(b-2) =0, which of the following must be true ?
I. a=1 and b=2
II. if a is not = 1, then b=2
III. if a=1, then b is not=2

A. I only
B. II only
C. III only
D. I and II
E. II and III

$$(a-1)(b-2) =0$$ --> either $$a=1$$ or $$b=2$$ (or both).

I. a=1 and b=2 --> not necessarily true: for example if a=1 then b can be any number
II. if a is not = 1, then b=2 --> if $$a\neq{1}$$ then in order $$(a-1)(b-2) =0$$ to hold true then $$b=2$$ MUST be true;
III. if a=1, then b is not=2 --> not necessarily true: $$a=1$$ and $$b=2$$ can be simultaneously true.

_________________
Manager
Joined: 07 Dec 2011
Posts: 174
Location: India
Followers: 1

Kudos [?]: 41 [0], given: 24

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

23 Mar 2012, 03:26
B. II only

I is not necessarily true as it makes both (a-1) and (b-2) equal zero which is not necessarily true. if either one of these were equal to zero it would satisfy the equation

II must be true. If a is not = 1 the (a-1)#0 there (b-2) must be equal to zero and b =2

III not necessarily true. It may be the case that a=1 and b=2 as this would lead to 0x0=0 which satisfies the equation.
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13437
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

03 Aug 2014, 19:43
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.
_________________
Manager
Joined: 11 Jun 2014
Posts: 57
Concentration: Technology, Marketing
GMAT 1: 770 Q50 V45
WE: Information Technology (Consulting)
Followers: 4

Kudos [?]: 33 [0], given: 3

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

03 Aug 2014, 20:30
(a-1)(b-2)=0
so either a=1 or b=2 or both. It 'or' not 'and', so it could be any of the three possibilities. so I and III cannot be always true.

so the answer is B, II only.
Current Student
Joined: 03 Aug 2014
Posts: 6
Concentration: Operations, Healthcare
GMAT 1: 730 Q48 V42
WE: Operations (Pharmaceuticals and Biotech)
Followers: 0

Kudos [?]: 0 [0], given: 6

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

03 Aug 2014, 20:48
if (a-1)(b-2) =0 then one of the following have to be true:

1. a = 1, and b can be any number
2. b = 2, and a can be any number
3. both and a = 1, b = 2

hope this helps
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13437
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

13 Nov 2015, 05:22
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.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13437
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: If (a-1)(b-2) =0, which of the following must be true ? [#permalink]

### Show Tags

23 Nov 2016, 05:45
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-1)(b-2) =0, which of the following must be true ?   [#permalink] 23 Nov 2016, 05:45
Similar topics Replies Last post
Similar
Topics:
If n > 0 , which of the following must be true? 3 12 May 2016, 00:55
4 If x>0, which of the following must be true? 2 13 Aug 2014, 09:18
7 If y + | y | = 0, which of the following must be true? 14 21 Apr 2012, 20:15
18 If у + |y| = 0, which of the following must be true? 8 18 Feb 2011, 09:16
10 If y + |y| = 0 which of the following must be true? 6 07 May 2010, 21:05
Display posts from previous: Sort by