Last visit was: 19 Nov 2025, 03:40 It is currently 19 Nov 2025, 03:40
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
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
User avatar
buckkitty
User avatar
Joined: 17 Aug 2005
Last visit: 29 Jul 2008
Posts: 222
Own Kudos:
1,170
Location: Boston, MA
Posts: 222
Kudos: 1,170
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 09:59
Kudos
Add Kudos
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
N
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

History

Date
Time
Result
Not Attempted Yet
What is the value of (a^-2)(b^-3)?

1) (a^-3)(b^-2)=36^-1
2) a(b^-1)=6^-1



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
User avatar
Gordon
User avatar
Joined: 24 Dec 2005
Last visit: 17 Sep 2012
Posts: 56
Own Kudos:
76
Posts: 56
Kudos: 76
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 10:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think its A. The only combination satisfying statement 1 seems to be when a=1 and b=6. is this the right answer?
User avatar
laxieqv
User avatar
Joined: 24 Sep 2005
Last visit: 24 Jun 2011
Posts: 831
Own Kudos:
1,525
Posts: 831
Kudos: 1,525
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 10:30
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Gordon
I think its A. The only combination satisfying statement 1 seems to be when a=1 and b=6. is this the right answer?
Show more


But a and b are not necessarily integers.
User avatar
buckkitty
User avatar
Joined: 17 Aug 2005
Last visit: 29 Jul 2008
Posts: 222
Own Kudos:
1,170
Location: Boston, MA
Posts: 222
Kudos: 1,170
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 10:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
vivek can you explain why you think it's C?
User avatar
laxieqv
User avatar
Joined: 24 Sep 2005
Last visit: 24 Jun 2011
Posts: 831
Own Kudos:
1,525
Posts: 831
Kudos: 1,525
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 10:38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
buckkitty
What is the value of (a^-2)(b^-3)?

1) (a^-3)(b^-2)=36^-1
2) a(b^-1)=6^-1
Show more


(a^-2)(b^-3)= ( a^-3)* a * (b^-2) * (b^-1) = [(a^-3)(b^-2)]*[a(b^-1)]
= 36^-1 * 6^-1 = 6^-3

That's why it's C.
User avatar
ywilfred
User avatar
Joined: 07 Jul 2004
Last visit: 06 Mar 2012
Posts: 1,989
Own Kudos:
2,031
Location: Singapore
Posts: 1,989
Kudos: 2,031
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 19:04
Kudos
Add Kudos
Bookmarks
Bookmark this Post
(a^-2)(b^-3) = 1/a^2(b^3)

(1) Not sufficient.

(2) Only know the ratio a/b. Insufficient.

Using both, we can work out 1/a^2(b^3).

(1)*(2) = 1/a^3(b^2) * a/b = 1/a^2(b^3) = 1/36 * 1/6

Sufficient.

Ans C(a^-2)(b^-3) = 1/a^2(b^3)
User avatar
gmat_crack
User avatar
Joined: 22 Nov 2005
Last visit: 04 Aug 2009
Posts: 209
Own Kudos:
71
Posts: 209
Kudos: 71
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 12 Mar 2006, 22:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
It C

When we multiply both statements we can get the value of

(a^-2)(b^-3)
User avatar
lhotseface
User avatar
Joined: 20 Sep 2005
Last visit: 18 Jan 2025
Posts: 798
Own Kudos:
53
Posts: 798
Kudos: 53
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 13 Mar 2006, 13:48
Kudos
Add Kudos
Bookmarks
Bookmark this Post
C. different approach.

1. a = 2^(2/3) and b = 3 OR a = 2 and b = 3^(2/3)...INSUFF.
2. b = 6a....INSUFF.

1+2 ...we can find a and b...SUFF.



buckkitty
What is the value of (a^-2)(b^-3)?

1) (a^-3)(b^-2)=36^-1
2) a(b^-1)=6^-1
Show more
User avatar
buckkitty
User avatar
Joined: 17 Aug 2005
Last visit: 29 Jul 2008
Posts: 222
Own Kudos:
1,170
Location: Boston, MA
Posts: 222
Kudos: 1,170
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 13 Mar 2006, 13:58
Kudos
Add Kudos
Bookmarks
Bookmark this Post
yes! and thanks for pointing this out, I had managed to overlook this. This seems much simpler to me....I am much less of a math guru than all of you :-D
User avatar
gmatkrishna
User avatar
Joined: 06 Mar 2006
Last visit: 19 Feb 2007
Posts: 19
Own Kudos:
2
Posts: 19
Kudos: 2
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 13 Mar 2006, 19:47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
My approach was

given 1/a^3 x 1/b^2 = 1/36 => (1)
a/b = 1/6 => (2) these are not sufficient by themselves

combining

(1) can be re-written as

1/a^2 x 1/b^2 = a/36

or

1/a^2 x 1/b^3 = a/b * 1/36

Substituting value for a/b from (2)
we have
1/a^2 x 1/b^3 = 1/6 x 1/36

Therefore, the answer is C
avatar
elektraa
avatar
Joined: 15 Mar 2006
Last visit: 23 Mar 2006
Posts: 8
Posts: 8
Kudos: 0
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 16 Mar 2006, 00:47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
laxieqv
buckkitty
What is the value of (a^-2)(b^-3)?

1) (a^-3)(b^-2)=36^-1
2) a(b^-1)=6^-1

(a^-2)(b^-3)= ( a^-3)* a * (b^-2) * (b^-1) = [(a^-3)(b^-2)]*[a(b^-1)]
= 36^-1 * 6^-1 = 6^-3

That's why it's C.
Show more


Can someone explain why the above is true? I still don't understand why.... Pls help :))
User avatar
cJackSparrow
User avatar
Joined: 09 Feb 2006
Last visit: 04 Apr 2006
Posts: 10
Own Kudos:
1
Location: Raleigh, NC
Posts: 10
Kudos: 1
What is the value of (a^-2)(b^-3)? 1) (a^-3)(b^-2)=36^-1 2) 16 Mar 2006, 06:46
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ans: C

(i) Only implies a^3 * b ^ 2 = 36 ; not sufficient. Eliminate A and D
(ii) Only implies a/b = 6 ; not suff Eliminate B
(i) and (ii)
Substitue a/b = 6 in (i), we get b^5=216*6, hence b = 6 ONLY => a = 1



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
Moderators:
Bunuel
Math Expert
105379 posts
GMATBusters
GMAT Tutor
1924 posts