NEW HERE? LEARN MORE
closeclose
Last visit was: 04 May 2024, 20:54 It is currently 04 May 2024, 20:54
Decision Tracker
My Rewards
New posts
New comers' posts

Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

Does ab= a^2

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
avatar
jsphcal
Intern
Intern
Joined: 27 Feb 2012
Posts: 27
Own Kudos [?]: 235 [10]
Given Kudos: 5
Send PM
Does ab= a^2 [#permalink] New post   18 Dec 2012, 22:51
2
Kudos
8
Bookmarks
00:00
A
B
C
D
E

Difficulty:

5% (low)

Question Stats:

79% (00:51) correct 21% (01:01) wrong based on 264 sessions
Hide Show timer Statistics
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3
ShowHide Answer
Official Answer
B
User avatar
MacFauz
VP
VP
Joined: 02 Jul 2012
Posts: 1005
Own Kudos [?]: 3124 [0]
Given Kudos: 116
Location: India
Concentration: Strategy
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
GPA: 3.8
WE:Engineering (Energy and Utilities)
Send PM
Re: Does ab= a^2 [#permalink] New post   18 Dec 2012, 23:02
jsphcal wrote:
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3


1) a = + or - b. If a = +b. Answer is yes. If a = -b. Answer is no. Insufficient.

2)a = b. Sufficient.

Answer is B.
avatar
jsphcal
Intern
Intern
Joined: 27 Feb 2012
Posts: 27
Own Kudos [?]: 235 [0]
Given Kudos: 5
Send PM
Re: Does ab= a^2 [#permalink] New post   18 Dec 2012, 23:15
MacFauz wrote:
jsphcal wrote:
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3


1) a = + or - b. If a = +b. Answer is yes. If a = -b. Answer is no. Insufficient.

2)a = b. Sufficient.

Answer is B.



MacFauz


thanks for the reply, could you please elaborate more on the algebra use to solve?

(1) and why if a= + or -b or if a = +b stmt 1 suff, and if a = -b then insuff

did you pick numbers to test stmt 1 and 2?
User avatar
shanmugamgsn
Manager
Manager
Joined: 04 Oct 2011
Posts: 144
Own Kudos [?]: 141 [3]
Given Kudos: 44
Location: India
Concentration: Entrepreneurship, International Business
GMAT 1: 440 Q33 V13
GPA: 3
Send PM
Re: Does ab= a^2 [#permalink] New post   18 Dec 2012, 23:27
3
Kudos
jsphcal wrote:
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3



\(ab=a^2\\
ab-a^2=0\\
a(b-a)=0\)

So we need a=0 or b=a

(1) doesnt help coz
\(a^2= b^2\)
\(a^2\) is + or - a
\(b^2\) is + or - b
We cant determine is it +ve or -ve
INSUFF

(2) helps
\(a^3= b^3\)
which means a=b or -a=-b
either way a=b
SUFF

Hence (B)
User avatar
MacFauz
VP
VP
Joined: 02 Jul 2012
Posts: 1005
Own Kudos [?]: 3124 [1]
Given Kudos: 116
Location: India
Concentration: Strategy
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
GPA: 3.8
WE:Engineering (Energy and Utilities)
Send PM
Re: Does ab= a^2 [#permalink] New post   18 Dec 2012, 23:27
1
Kudos
jsphcal wrote:
MacFauz wrote:
jsphcal wrote:
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3


1) a = + or - b. If a = +b. Answer is yes. If a = -b. Answer is no. Insufficient.

2)a = b. Sufficient.

Answer is B.



MacFauz


thanks for the reply, could you please elaborate more on the algebra use to solve?

(1) and why if a= + or -b or if a = +b stmt 1 suff, and if a = -b then insuff

did you pick numbers to test stmt 1 and 2?


1. We do not need to pick numbers.

1) \(a^2 = b^2\)
This means + or - a = + or - b. So we are basically given that a can be equal to b or a can be equal to -b.

If a = b, LHS of given equation becomes a^2 and hence is equal to RHS
If a = -b, LHS of given equation becomes -a^2 and hence may not be equal to RHS.

Since we are getting two different answers, this statement is insufficient.

2) \(a^3 = b^3\)
This means a = b and nothing else.

So, LHS of given equation can only be a^2 and hence is equal to RHS. Sufficient.
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 93029
Own Kudos [?]: 621235 [1]
Given Kudos: 81745
Send PM
CAT Tests Forum Quiz Mode
Re: Does ab= a^2 [#permalink] New post   19 Dec 2012, 02:47
1
Kudos
Expert Reply
Does ab = a^2

Does \(ab = a^2\)? --> does \(a(a-b)=0\)? does \(a=0\) or \(a=b\)?

(1) a^2 = b ^2 --> \(a=b\) or \(a=-b\). Not sufficient.

(2) a^3 = b ^3 --> \(a=b\). Sufficient.

Answer: B.
avatar
fozzzy
Director
Director
Joined: 29 Nov 2012
Posts: 580
Own Kudos [?]: 6054 [0]
Given Kudos: 543
Send PM
Does ab= a^2? [#permalink] New post   Updated on: 17 Sep 2013, 02:16
Does \(ab= a^2\)?

(1) \(a^2 = b^2\)
(2) \(a^3 = b^3\)

Originally posted by fozzzy on 17 Sep 2013, 02:04.
Last edited by fozzzy on 17 Sep 2013, 02:16, edited 1 time in total.
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 93029
Own Kudos [?]: 621235 [1]
Given Kudos: 81745
Send PM
CAT Tests Forum Quiz Mode
Re: Does ab= a^2? [#permalink] New post   17 Sep 2013, 02:09
1
Kudos
Expert Reply
Does ab= a^2?

Does ab= a^2? --> does a=0 or a=b?

(1) a^2 = b^2 --> |a| = |b|. Not sufficient. (Consider a=b=1 for an YES answer and a=1 and b=-1 for a NO answer.)

(2) a^3 = b^3 --> a = b. Sufficient.

Answer: B.
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32799
Own Kudos [?]: 826 [0]
Given Kudos: 0
Send PM
Re: Does ab= a^2 [#permalink] New post   29 Nov 2022, 01:08
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.
GMAT Club Bot
gmatclubot
Re: Does ab= a^2 [#permalink]
29 Nov 2022, 01:08
Moderator:
Bunuel
Math Expert
93029 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions