Last visit was: 24 Apr 2026, 05:15 It is currently 24 Apr 2026, 05:15
Home
Messages
Tests
Schools
Events
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
Back to Forum
Create Topic
505-555 (Easy)|   Algebra|      
avatar
jsphcal
avatar
Joined: 27 Feb 2012
Last visit: 27 Feb 2014
Posts: 26
Own Kudos:
291
 [12]
Given Kudos: 5
Posts: 26
Kudos: 291
 [12]
Does ab= a^2 18 Dec 2012, 22:51
2
Kudos
Add Kudos
10
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

15% (low)

Question Stats:

79% (00:51) correct 21% (01:01) wrong based on 327 sessions

History

Date
Time
Result
Not Attempted Yet
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3
ShowHide Answer
Official Answer
B
Solving this question helps. Taking a timed set of similar questions in GMAT Club Forum Quiz → is even better.
User avatar
MacFauz
User avatar
Joined: 02 Jul 2012
Last visit: 19 Mar 2022
Posts: 990
Own Kudos:
3,406
Given Kudos: 116
Location: India
Concentration: Strategy
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
GPA: 3.8
WE:Engineering (Energy)
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
Posts: 990
Kudos: 3,406
Does ab= a^2 18 Dec 2012, 23:02
Kudos
Add Kudos
Bookmarks
Bookmark this Post
jsphcal
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3
Show more

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
avatar
Joined: 27 Feb 2012
Last visit: 27 Feb 2014
Posts: 26
Own Kudos:
291
Given Kudos: 5
Posts: 26
Kudos: 291
Does ab= a^2 18 Dec 2012, 23:15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
MacFauz
jsphcal
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.
Show more


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
User avatar
Joined: 04 Oct 2011
Last visit: 31 Dec 2014
Posts: 140
Own Kudos:
160
 [3]
Given Kudos: 44
Location: India
Concentration: Entrepreneurship, International Business
GMAT 1: 440 Q33 V13
GPA: 3
GMAT 1: 440 Q33 V13
Posts: 140
Kudos: 160
 [3]
Does ab= a^2 18 Dec 2012, 23:27
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
jsphcal
Does ab = a^2

(1) a^2 = b ^2

(2) a^3 = b ^3
Show more


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

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
User avatar
Joined: 02 Jul 2012
Last visit: 19 Mar 2022
Posts: 990
Own Kudos:
3,406
 [1]
Given Kudos: 116
Location: India
Concentration: Strategy
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
GPA: 3.8
WE:Engineering (Energy)
Schools: Ross '16 (D) McCombs '16 (D) Kenan-Flagler '16 (WA) Olin '16 (M$) Tepper '16 (D)
GMAT 1: 740 Q49 V42
Posts: 990
Kudos: 3,406
 [1]
Does ab= a^2 18 Dec 2012, 23:27
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
jsphcal
MacFauz
jsphcal
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?
Show more

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
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,811
Own Kudos:
810,958
 [1]
Given Kudos: 105,869
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,811
Kudos: 810,958
 [1]
Does ab= a^2 19 Dec 2012, 02:47
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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
avatar
Joined: 29 Nov 2012
Last visit: 17 May 2015
Posts: 573
Own Kudos:
7,003
Given Kudos: 543
Posts: 573
Kudos: 7,003
Does ab= a^2 Updated on: 17 Sep 2013, 02:16
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.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Does \(ab= a^2\)?

(1) \(a^2 = b^2\)
(2) \(a^3 = b^3\)
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,811
Own Kudos:
810,958
 [1]
Given Kudos: 105,869
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,811
Kudos: 810,958
 [1]
Does ab= a^2 17 Sep 2013, 02:09
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,974
Own Kudos:
1,117
Posts: 38,974
Kudos: 1,117
Does ab= a^2 15 Oct 2024, 21:28
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109811 posts
kingbucky
498 posts
Gmat860sanskar
212 posts