Last visit was: 24 Apr 2026, 21:02 It is currently 24 Apr 2026, 21:02
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.
Close
Request Expert Reply
Confirm Cancel
User avatar
lifeisshort
Joined: 11 Mar 2010
Last visit: 25 Feb 2012
Posts: 53
Own Kudos:
61
 [6]
Given Kudos: 6
Posts: 53
Kudos: 61
 [6]
1
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
seekmba
Joined: 17 Feb 2010
Last visit: 25 Sep 2014
Posts: 626
Own Kudos:
3,644
 [12]
Given Kudos: 6
Posts: 626
Kudos: 3,644
 [12]
10
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
General Discussion
User avatar
mainhoon
Joined: 18 Jul 2010
Last visit: 10 Oct 2013
Posts: 532
Own Kudos:
397
 [1]
Given Kudos: 15
Status:Apply - Last Chance
Affiliations: IIT, Purdue, PhD, TauBetaPi
Concentration: $ Finance $
Schools:Wharton, Sloan, Chicago, Haas
GPA: 4.0
WE 1: 8 years in Oil&Gas
Posts: 532
Kudos: 397
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
lifeisshort
Joined: 11 Mar 2010
Last visit: 25 Feb 2012
Posts: 53
Own Kudos:
Given Kudos: 6
Posts: 53
Kudos: 61
Kudos
Add Kudos
Bookmarks
Bookmark this Post
mainhoon
Is answer 2?

If just looked at 5 then we have 5^(x+1) = 5^3

Posted from my mobile device

How can we assume five-to-the-x-power, (5^x), is actually 5^x plus "some other number"? If that was the intention of the problem, then the problem would show (5^(x+1)) not (5^x)...right?

And in anycase, how did you decide on the answer choice? How do you know what the answer is....
User avatar
mainhoon
Joined: 18 Jul 2010
Last visit: 10 Oct 2013
Posts: 532
Own Kudos:
Given Kudos: 15
Status:Apply - Last Chance
Affiliations: IIT, Purdue, PhD, TauBetaPi
Concentration: $ Finance $
Schools:Wharton, Sloan, Chicago, Haas
GPA: 4.0
WE 1: 8 years in Oil&Gas
Posts: 532
Kudos: 397
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I got the extra 5 from 20. I wa isolating all the 5s in one place.. So is it 2?

Posted from my mobile device
User avatar
lifeisshort
Joined: 11 Mar 2010
Last visit: 25 Feb 2012
Posts: 53
Own Kudos:
Given Kudos: 6
Posts: 53
Kudos: 61
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I don't know the answer, unfortunately. Anyone able to offer a solution/explanation for this problem?
User avatar
mainhoon
Joined: 18 Jul 2010
Last visit: 10 Oct 2013
Posts: 532
Own Kudos:
397
 [1]
Given Kudos: 15
Status:Apply - Last Chance
Affiliations: IIT, Purdue, PhD, TauBetaPi
Concentration: $ Finance $
Schools:Wharton, Sloan, Chicago, Haas
GPA: 4.0
WE 1: 8 years in Oil&Gas
Posts: 532
Kudos: 397
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ok so I took a calculator out and here is the bottom-line
5^x = 18.59, it's not a clean figure, I don't know why
But closest has to be 2..

Posted from my mobile device
User avatar
lifeisshort
Joined: 11 Mar 2010
Last visit: 25 Feb 2012
Posts: 53
Own Kudos:
Given Kudos: 6
Posts: 53
Kudos: 61
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ooops, I must apologize because I made a blunder in my copy/paste of this equation.
(62) should be (6^2), six-to-the-power-of-two.

So, does this change your answer...if not, can you elaborate more on how exactly you arrived at your solution? THanks.
User avatar
runnergirl
User avatar
Stanford School Moderator
Joined: 03 Aug 2010
Last visit: 03 Apr 2013
Posts: 184
Own Kudos:
Given Kudos: 68
Schools:Booth
GPA: 3.39
Posts: 184
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Are you sure that the denominator is correct? 1,375 factors to 11 * 5^3. The denominator factors to 41*2*3*3. There is no other 41 in the equation to cancel out. Further, 41 is a prime number. It just seems to me that this is the sort of problem where most other numbers will cancel out and you would be left with 5^x = 5^3.
User avatar
mainhoon
Joined: 18 Jul 2010
Last visit: 10 Oct 2013
Posts: 532
Own Kudos:
Given Kudos: 15
Status:Apply - Last Chance
Affiliations: IIT, Purdue, PhD, TauBetaPi
Concentration: $ Finance $
Schools:Wharton, Sloan, Chicago, Haas
GPA: 4.0
WE 1: 8 years in Oil&Gas
Posts: 532
Kudos: 397
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I would say x is still 2 as your correction did not introduce any more 5s... Doublecheck with calc but 6^2 still doesn't work

lifeisshort
Ooops, I must apologize because I made a blunder in my copy/paste of this equation.
(62) should be (6^2), six-to-the-power-of-two.

So, does this change your answer...if not, can you elaborate more on how exactly you arrived at your solution? THanks.

Posted from my mobile device
User avatar
lifeisshort
Joined: 11 Mar 2010
Last visit: 25 Feb 2012
Posts: 53
Own Kudos:
Given Kudos: 6
Posts: 53
Kudos: 61
Kudos
Add Kudos
Bookmarks
Bookmark this Post
runnergirl683
Are you sure that the denominator is correct? 1,375 factors to 11 * 5^3. The denominator factors to 41*2*3*3. There is no other 41 in the equation to cancel out. Further, 41 is a prime number. It just seems to me that this is the sort of problem where most other numbers will cancel out and you would be left with 5^x = 5^3.

Gosh, yes I see the denominator was incorrect; it should be (8^2), I made the change.
The problem is now correct....and with a quick calculator check, the answer should be 2 (answer D).

But is there anyway to do this OTHER than doing ALL of that LONG-hand multiplication and LONG-hand division? It takes too much time and increases the chance I'll make an error.

What is the shortcut?
User avatar
mainhoon
Joined: 18 Jul 2010
Last visit: 10 Oct 2013
Posts: 532
Own Kudos:
Given Kudos: 15
Status:Apply - Last Chance
Affiliations: IIT, Purdue, PhD, TauBetaPi
Concentration: $ Finance $
Schools:Wharton, Sloan, Chicago, Haas
GPA: 4.0
WE 1: 8 years in Oil&Gas
Posts: 532
Kudos: 397
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Well, as I have been saying in my earlier posts above the shortest method indeed is:
5^(x+1) = 5^3
x=>2

Just compare the powers of 5 on both sides. I can't imagine anything shorter than this.
User avatar
Phaser
Joined: 03 Mar 2010
Last visit: 06 May 2012
Posts: 12
Own Kudos:
Given Kudos: 2
Status:In Quiet Contemplation
Concentration: Social Entrepreurship, Strategic Management
GPA: 3.88
WE 1: General Management: Plastics Manufacturing (7 years)
Posts: 12
Kudos: 30
Kudos
Add Kudos
Bookmarks
Bookmark this Post
seekmba
The attached should help.

Yup, that's how I did it. I think what we must remember in this case is that most of the time, GMAT problems that appear to require complex calculations can often be simplified to very manageable proportions.
User avatar
aim730
Joined: 20 Apr 2010
Last visit: 30 Sep 2023
Posts: 166
Own Kudos:
Given Kudos: 66
Concentration: Tuck,Cornell,Duke
WE 1: 4.6 years Exp IT prof
Products:
GMAT 3: 710 Q49 V38
Posts: 166
Kudos: 72
Kudos
Add Kudos
Bookmarks
Bookmark this Post
You can do it two ways Either by solving the whole equation or by considering 1375 and it's factor with the factors on the other side
for full explanation Seekmba has given right but long explanation
another the shorter version
The whole equation on the left side when solved should be equal to the 1375
the factors of 1375 are 5*5*5*11
that means all this value will be present on the left side of the equation
and rest all will cancel each other out
Moreover we are not concerned about any powers of 2,3 and 11
we are only concerned with the power of 5
so we will search for the 5 as factor for the equation on the left
it comes out to be 5^x and 5 as a factor of 20
Hence 5^x*5 = 5^3
that is all what is required therefore the answer for x is 2
i.e. D
User avatar
hirendhanak
User avatar
Retired Moderator
Joined: 03 Aug 2010
Last visit: 13 Oct 2012
Posts: 144
Own Kudos:
120
 [1]
Given Kudos: 41
Posts: 144
Kudos: 120
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
easy one if you prime factorise every term with 2 and 3 , just discard all possible and you are left with only one prime "5" to be operated
avatar
PareshGmat
Joined: 27 Dec 2012
Last visit: 10 Jul 2016
Posts: 1,531
Own Kudos:
Given Kudos: 193
Status:The Best Or Nothing
Location: India
Concentration: General Management, Technology
WE:Information Technology (Computer Software)
Posts: 1,531
Kudos: 8,274
Kudos
Add Kudos
Bookmarks
Bookmark this Post
\(\frac{6^2* 44* 5^x *20}{8^2 *9} = 1375\)

\(5^{x+1} = 125\)

x+1 = 3

x = 2

Answer = D
avatar
neowacka
Joined: 18 Sep 2014
Last visit: 18 Jun 2015
Posts: 1
Given Kudos: 18
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
PareshGmat
\(\frac{6^2* 44* 5^x *20}{8^2 *9} = 1375\)

\(5^{x+1} = 125\)

x+1 = 3

x = 2

Answer = D

Can you explain this? Can't get it :(
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,818
Own Kudos:
Given Kudos: 105,873
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,818
Kudos: 811,088
Kudos
Add Kudos
Bookmarks
Bookmark this Post
neowacka
PareshGmat
\(\frac{6^2* 44* 5^x *20}{8^2 *9} = 1375\)

\(5^{x+1} = 125\)

x+1 = 3

x = 2

Answer = D

Can you explain this? Can't get it :(

Explained here: if-6-2-44-5-x-20-8-2-9-1375-what-is-the-value-of-x-99494.html#p768504
avatar
hatemnag
Joined: 20 Apr 2014
Last visit: 19 Jan 2020
Posts: 65
Own Kudos:
Given Kudos: 50
Posts: 65
Kudos: 17
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think we need to know the prime factors of 1375 then we must cancel out any prime factor different from the other side and complete the missing power of common prime factors.
1375 = 11 x 5 power 3 so there is no need for 2 or 3 on the other side. so 5 and 11 must have missing power which is 5 power 2
x = 2
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,976
Own Kudos:
Posts: 38,976
Kudos: 1,117
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:
Math Expert
109818 posts
Tuck School Moderator
853 posts