It is currently 22 Jun 2017, 05:34

### 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

# Did this on the GMATprep - and I swear I got it right, but

 post reply Question banks Downloads My Bookmarks Reviews Important topics

### What do you think the answer is?

• 75% [3]
• 0% [0]
• 0% [0]
• 25% [1]
• 0% [0]
Author Message
Manager
Joined: 25 Aug 2007
Posts: 70
Schools: HBS '10
Did this on the GMATprep - and I swear I got it right, but [#permalink]

### Show Tags

25 Aug 2007, 19:35
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Did this on the GMATprep - and I swear I got it right, but the original answer suggests differently.

2^(4-1)^2 / 2^(3-2)

A. 2^8
B. 2^7
C. 2^6
D. 2^5
E. 2^4

I'm convinced that my answer is D (highlight to see)

But the OA is A (highlight to see)...
VP
Joined: 10 Jun 2007
Posts: 1438
Re: Question on exponentials [#permalink]

### Show Tags

25 Aug 2007, 20:36
Big-O wrote:
Did this on the GMATprep - and I swear I got it right, but the original answer suggests differently.

2^(4-1)^2 / 2^(3-2)

A. 2^8
B. 2^7
C. 2^6
D. 2^5
E. 2^4

I'm convinced that my answer is D (highlight to see)

But the OA is A (highlight to see)...

You can think of this two way, which are totally different. Let's just consider the top part...
2^(4-1)^2
This can be seen as: (2^3)^2 = 2^6
OR
2^(3^2) = 2^9
The latter will give you the right answer. I imagine in GMATprep, it should be pretty clear. Do you have a snapshot of the problem?
Manager
Joined: 25 Aug 2007
Posts: 70
Schools: HBS '10

### Show Tags

25 Aug 2007, 21:38
Here is the screenshot (I haven't been around enough to directly hotlink

A^B^C is the same as A^BC, therefore the top gives 2^6, not 2^9...
Attachments

Question.JPG [ 4.06 KiB | Viewed 751 times ]

VP
Joined: 08 Jun 2005
Posts: 1145

### Show Tags

25 Aug 2007, 22:09
edited post

Its a simple case of BEDMAS

2^3^2 = 2^(3^2) = 512

not (2^3)^2 = 64

Don't check this in Excel spreadsheet. Excel will yield 64 for 2^3^2 this is wrong !

Last edited by KillerSquirrel on 26 Aug 2007, 00:49, edited 2 times in total.
VP
Joined: 10 Jun 2007
Posts: 1438

### Show Tags

25 Aug 2007, 22:14
Thanks for the shot. I would have get 2^9 for the top, but I agree it is a bit unclear.
VP
Joined: 08 Jun 2005
Posts: 1145

### Show Tags

25 Aug 2007, 23:43
see edited post above !

Last edited by KillerSquirrel on 26 Aug 2007, 00:48, edited 1 time in total.
VP
Joined: 10 Jun 2007
Posts: 1438

### Show Tags

25 Aug 2007, 23:47
KillerSquirrel wrote:
bkk145 wrote:
Thanks for the shot. I would have get 2^9 for the top, but I agree it is a bit unclear.

I see the operation of (4-1)^2 = 9 first.
Otherwise, I feel that there should have been parenthesizes like this:
(2^(4-1))^2
25 Aug 2007, 23:47
Display posts from previous: Sort by

# Did this on the GMATprep - and I swear I got it right, but

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.