Which of the following is closest in value to (9^9)-(9^2)? : 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, 14:53

### 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

# Which of the following is closest in value to (9^9)-(9^2)?

Author Message
TAGS:

### Hide Tags

Manager
Joined: 23 Mar 2008
Posts: 219
Followers: 3

Kudos [?]: 143 [0], given: 0

Which of the following is closest in value to (9^9)-(9^2)? [#permalink]

### Show Tags

24 May 2008, 11:33
2
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

68% (01:37) correct 32% (00:42) wrong based on 395 sessions

### HideShow timer Statistics

Which of the following is closest in value to (9^9)-(9^2)?

A. 9^9
B. 9^8
C. 9^7
D. 9^6
E. 9^5
[Reveal] Spoiler: OA

Last edited by Bunuel on 26 Feb 2014, 00:23, edited 2 times in total.
Renamed the topic, edited the question and added the OA.
SVP
Joined: 30 Apr 2008
Posts: 1887
Location: Oklahoma City
Schools: Hard Knocks
Followers: 40

Kudos [?]: 570 [1] , given: 32

### Show Tags

24 May 2008, 11:53
1
KUDOS
I think the answer is going to be A. The reason is that subtracting 81 from 9^9 is not going to subtract enough to get it anywhere close to 9^8. 9^8 is going to be such a huge number that when you multiply it by 9 again to get 9^9, subtracting 81 (i.e., 9^2) from it, the result will still be must closer to 9^9 than any of the others.

puma wrote:
Which of the following is closest in value to (9^9)-(9^2)?

a) 9^9
b) 9^8
c) 9^7
d) 9^6
e) 9^5

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a.

GMAT Club Premium Membership - big benefits and savings

SVP
Joined: 28 Dec 2005
Posts: 1575
Followers: 3

Kudos [?]: 147 [2] , given: 2

### Show Tags

24 May 2008, 15:24
2
KUDOS
1
This post was
BOOKMARKED
i would say A as well ... i just simplified out to 9^2*(9^7 - 1) ... and the 1 is pretty much negligible ... so we go back down to 9^9 ...
Joined: 20 Aug 2009
Posts: 311
Location: Tbilisi, Georgia
Schools: Stanford (in), Tuck (WL), Wharton (ding), Cornell (in)
Followers: 18

Kudos [?]: 140 [0], given: 69

### Show Tags

26 Nov 2009, 12:37
gmat620 wrote:
isn't there any algebraic solution ?

We need to get approximate answer. I'm pretty sure exact number is unreachable w/o Excel spreadsheets.
Manager
Joined: 14 Apr 2010
Posts: 230
Followers: 2

Kudos [?]: 149 [0], given: 1

Which of the following is closest to 9^9 - 9^2? [#permalink]

### Show Tags

09 May 2010, 22:30
Which of the following is closest to 9^9 - 9^2?

A. 9^9
B. 9^8
C. 9^7
D. 9^6
E. 9^5
CEO
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2795
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 226

Kudos [?]: 1619 [0], given: 235

### Show Tags

09 May 2010, 22:50
bibha wrote:
1. which of the following is closest to 9^9 - 9^2?
9^9
9^8
9^7
9^6
9^5

What is the trick?>>???

IMO A, whats the OA?

clearly 9^8 <9^9 - 9^2 < 9^9
now 9^9 - 9^2 will be closer to 9^9 if 9^9 - 9^2? lies between $$\frac{(9^9+9^8)}{2}$$ and 9^9 else 9^8
$$\frac{(9^9+9^8)}{2}$$ = $$9^8*\frac{(9+1)}{2} = 9^{8} * 5$$

$$9^9 - 9^2 = 9^8( 9 - 9^{-6}) > 9^8 * 8 > 9^8*5$$

since 9^9 - 9^2 is greater than $$\frac{(9^9+9^8)}{2}$$ i.e $$9^{8} * 5$$

This lies closer to 9^9
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned

Jo Bole So Nihaal , Sat Shri Akaal

GMAT Club Premium Membership - big benefits and savings

Gmat test review :
http://gmatclub.com/forum/670-to-710-a-long-journey-without-destination-still-happy-141642.html

Math Expert
Joined: 02 Sep 2009
Posts: 36548
Followers: 7077

Kudos [?]: 93107 [3] , given: 10552

### Show Tags

10 May 2010, 15:40
3
KUDOS
Expert's post
3
This post was
BOOKMARKED
bibha wrote:
1. which of the following is closest to 9^9 - 9^2?
9^9
9^8
9^7
9^6
9^5

What is the trick?>>???

Easier way: $$9^9 - 9^2=9^2(9^7-1)$$. Now $$9^7-1$$ is very close to $$9^7$$, hence $$9^9 - 9^2=9^2(9^7-1)\approx{9^2*9^7=9^9}$$.

_________________
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 47

Kudos [?]: 1929 [0], given: 193

Re: Which of the following is closest in value to (9^9)-(9^2)? [#permalink]

### Show Tags

25 Feb 2014, 19:58
puma wrote:
Which of the following is closest in value to (9^9)-(9^2)?

a) 9^9
b) 9^8
c) 9^7
d) 9^6
e) 9^5

9^9 is way too high compared to 9^2
_________________

Kindly press "+1 Kudos" to appreciate

Math Expert
Joined: 02 Sep 2009
Posts: 36548
Followers: 7077

Kudos [?]: 93107 [0], given: 10552

Re: Which of the following is closest in value to (9^9)-(9^2)? [#permalink]

### Show Tags

26 Feb 2014, 00:25
Expert's post
1
This post was
BOOKMARKED
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 47

Kudos [?]: 1929 [0], given: 193

Re: Which of the following is closest to 9^9 - 9^2? [#permalink]

### Show Tags

02 Apr 2014, 01:19
$$9^9$$ is way too high than $$9^2$$

$$So answer = A = 9^9$$
_________________

Kindly press "+1 Kudos" to appreciate

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13438
Followers: 575

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

Re: Which of the following is closest in value to (9^9)-(9^2)? [#permalink]

### Show Tags

26 Jun 2015, 07:56
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: 13438
Followers: 575

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

Re: Which of the following is closest in value to (9^9)-(9^2)? [#permalink]

### Show Tags

17 Sep 2016, 04:12
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: Which of the following is closest in value to (9^9)-(9^2)?   [#permalink] 17 Sep 2016, 04:12
Similar topics Replies Last post
Similar
Topics:
2 Of the following, which if closest to ? 4 26 Dec 2016, 01:39
3 Which of the following is closest to the value of (2^23)(5^26)? 1 24 Nov 2016, 02:03
If x2 = 131, which of the following is closest to a potential value of 3 17 Feb 2016, 02:58
2 Which of the following is closest to the value of 999/(100+1/999)? 2 26 Jan 2016, 09:30
14 Of the following integers which is the closest approximation 9 14 May 2010, 07:34
Display posts from previous: Sort by