Last visit was: 07 Sep 2026, 07:29 It is currently 07 Sep 2026, 07:29
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
Sub 505 (Easy)|   Exponents|      
User avatar
shridhar786
User avatar
Joined: 31 May 2018
Last visit: 08 Feb 2022
Posts: 322
Own Kudos:
1,793
 [2]
Given Kudos: 132
Location: United States
Concentration: Finance, Marketing
Posts: 322
Kudos: 1,793
 [2]
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 01 Aug 2019, 12:36
Kudos
Add Kudos
2
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:

5% (low)

Question Stats:

78% (00:52) correct 22% (00:58) wrong based on 195 sessions

History

Date
Time
Result
Not Attempted Yet
\(P = a^4*b^7\), where \(a^2 = 1\) and \(b^2 = 9\). What is the value of P?


(1) a < 0

(2) b < 0
ShowHide Answer
Official Answer
B
User avatar
Staphyk
User avatar
Joined: 20 Mar 2018
Last visit: 30 Jan 2022
Posts: 466
Own Kudos:
381
 [1]
Given Kudos: 149
Location: Ghana
Concentration: Finance, Statistics
GMAT 1: 710 Q49 V39
Products:
My Reviews
GMAT 1: 710 Q49 V39
Posts: 466
Kudos: 381
 [1]
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 01 Aug 2019, 13:36
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Wrong tag it should be sub-600 level i think so
P=a^4•b^7 ,where a^2=1 and b^2=9 What is the value of P?


(1) a < 0
So a= -ve ,no information on b and it can be +ve/-ve
P=(-ve)^4•(+ve)^7 =+ve numbers
However, P=(-ve)^4•(-ve)^7 =-ve number
Not sufficient :(

(2) b < 0
b=-ve,no info. on a can be +ve/-ve
P=(-ve)^4•(-ve)^7=-ve number
Also ,P=(+ve)^4•(-ve)^7=-ve number
Sufficient :)

Smack that B!

Posted from my mobile device
avatar
Hadiagh
avatar
Joined: 01 Sep 2020
Last visit: 04 Jan 2022
Posts: 14
Own Kudos:
1
Given Kudos: 101
Posts: 14
Kudos: 1
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 09 Jun 2021, 06:33
Kudos
Add Kudos
Bookmarks
Bookmark this Post
can someone please give a little more clarity on why B is the correct answer.
B will only tell us the sign of the value of P but it does not actually helps us figure out the value of P.
and P= -ve could be any value so like wouldn't statement 2 be insufficient.



please help
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 07 Sep 2026
Posts: 113,193
Own Kudos:
839,726
 [2]
Given Kudos: 111,359
Products:
GMAT Club Tests
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 113,193
Kudos: 839,726
 [2]
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 09 Jun 2021, 09:19
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hadiagh
can someone please give a little more clarity on why B is the correct answer.
B will only tell us the sign of the value of P but it does not actually helps us figure out the value of P.
and P= -ve could be any value so like wouldn't statement 2 be insufficient.



please help
Show more


\(P = a^4*b^7\), where \(a^2 = 1\) and \(b^2 = 9\). What is the value of P?

Since \(a^2 = 1\), then \(a^4=1\);
Since \(b^2 = 9\), then \(b=3\) or \(b=-3\).

Therefore, \(P =3^7\) or \(P=(-3)^7\)

Basically to get the value of P we only need to know whether b is positive or negative.

(1) a < 0. Not sufficient.

(2) b < 0 --> \(b=-3\) --> \(P=(-3)^7\). Sufficient.

Answer: B.
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 07 Sep 2026
Posts: 6,129
Own Kudos:
6,090
Given Kudos: 164
Location: India
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
My Reviews
Schools: HBS '26 CBS '26 Wharton '26
GMAT 1: 690 Q50 V34
Posts: 6,129
Kudos: 6,090
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 09 Jun 2021, 09:44
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Given: \(P = a^4*b^7\), where \(a^2 = 1\) and \(b^2 = 9\).
Asked: What is the value of P?

a = 1 or -1
b = 3 or -3

(1) a < 0
a = -1
\(P = a^4*b^7= 1*b^7\)
P = 3^7 or -3^7
NOT SUFFICIENT

(2) b < 0
b = -3
\(P = a^4*b^7= 1*(-3)^7= - 3^7\)
SUFFICIENT

IMO B
avatar
Hadiagh
avatar
Joined: 01 Sep 2020
Last visit: 04 Jan 2022
Posts: 14
Own Kudos:
1
Given Kudos: 101
Posts: 14
Kudos: 1
P = a^4*b^7, where a^2 = 1 and b^2 = 9. What is the value of P? 10 Jun 2021, 03:56
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Hadiagh
can someone please give a little more clarity on why B is the correct answer.
B will only tell us the sign of the value of P but it does not actually helps us figure out the value of P.
and P= -ve could be any value so like wouldn't statement 2 be insufficient.



please help


\(P = a^4*b^7\), where \(a^2 = 1\) and \(b^2 = 9\). What is the value of P?

Since \(a^2 = 1\), then \(a^4=1\);
Since \(b^2 = 9\), then \(b=3\) or \(b=-3\).

Therefore, \(P =3^7\) or \(P=(-3)^7\)

Basically to get the value of P we only need to know whether b is positive or negative.

(1) a < 0. Not sufficient.

(2) b < 0 --> \(b=-3\) --> \(P=(-3)^7\). Sufficient.

Answer: B.
Show more







okay yes that helped thankyou...
Moderators:
Bunuel
Math Expert
113193 posts
FrozenDragon
DI Forum Moderator
409 posts