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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

I think there is some problem with either the values in the ques stem or the ans choices. something is wrong. What is the source of this ques? _________________

Happy Learning ! :D

Show Thanks to fellow members with Kudos its shows your appreciation and its free

Q. What is the value of 11x-11(x^+2) where x is the largest integer such that 11x is a factor of 30030?

a) -1331 b) -1320 c) -121 d) -120 e) -1

The given expression is \(11x - 11x^2\) = \(11x (1 - x)\)

11x needs to be factor of 30030 and x needs to be the largest integer possible. This means 11x needs to be the largest factor possible. The largest factor of a number is the number itself. The largest factor of 30030 is 30030 = (11 * 2730) x must be 2730

The value of 11x(1-x) = 30030*(-2729) There is definitely something wrong in the expression, either in the book or in this particular reproduction. _________________

Re: What is the value of 11^x-11^(x+2) where x is the largest [#permalink]

Show Tags

14 Jul 2012, 03:32

1

This post received KUDOS

Expert's post

pavanpuneet wrote:

how did we infer that x=1?

We have that \(30,030=2*3*5*7*11*13\) is divisible by \(11^x\) (where \(x\) is an integer). Now, ask yourself what can be the largest integer value of \(x\). Could it be 2 or more? _________________

Re: What is the value of 11^x-11^(x+2) where x is the largest [#permalink]

Show Tags

05 Nov 2012, 04:53

Here 30030/11 gives 2730. This cannot be divided further and hence 11 can have the power of only 1. substituting in the given equation gives the ans -1320. _________________

I've failed over and over and over again in my life and that is why I succeed--Michael Jordan Kudos drives a person to better himself every single time. So Pls give it generously Wont give up till i hit a 700+

Re: What is the value of 11^x-11^(x+2) where x is the largest [#permalink]

Show Tags

10 Dec 2012, 06:56

Given x is the largest integer 30030

Find the Value of 11^x - 11^(x + 2)

Simplify 11^x - 11^(x + 2) we get (11^x)(1-11^2) -> (11^x)(1-11)(1+11) -> (11^x)(-10)(12)

Elimination (11^x)(-10)(12) 1.From this we know that the value has to be -ve 2.The units digit must be a 0.

Hence eliminate options A,C,E. Now we are left with B and D

Look at the equation again (11^x)(-10)(12) -> (11^x)(-120) Now in option D we have -120 this can possible only if x is the above equation is 0. However we are told that 11^X is a factor of 30030. So x has to be greater than 0. Which eliminates the option D.

Re: What is the value of 11^x-11^(x+2) where x is the largest [#permalink]

Show Tags

10 Dec 2012, 07:21

Expert's post

maddyboiler wrote:

Given x is the largest integer 30030

Find the Value of 11^x - 11^(x + 2)

Simplify 11^x - 11^(x + 2) we get (11^x)(1-11^2) -> (11^x)(1-11)(1+11) -> (11^x)(-10)(12)

Elimination (11^x)(-10)(12) 1.From this we know that the value has to be -ve 2.The units digit must be a 0.

Hence eliminate options A,C,E. Now we are left with B and D

Look at the equation again (11^x)(-10)(12) -> (11^x)(-120) Now in option D we have -120 this can possible only if x is the above equation is 0. However we are told that 11^X is a factor of 30030. So x has to be greater than 0. Which eliminates the option D.

Answer is B

11^x would be a factor of 30,030 even if x=0, since 11^0=1 and 1 is a factor of every integer. The point is that we are looking for the largest possible value of integer x such that 11^x is a factor of 30,030, which is for x=1.

Re: What is the value of 11^x-11^(x+2) where x is the largest [#permalink]

Show Tags

10 Dec 2012, 08:09

Agree. So just to make sure we can see if 30030 is divisible by 11. If it is then we really dont care by how much because we know that x is not 0 now. So the only option we are left with is now B.

Part 2 of the GMAT: How I tackled the GMAT and improved a disappointing score Apologies for the month gap. I went on vacation and had to finish up a...

I’m a little delirious because I’m a little sleep deprived. But whatever. I have to write this post because... I’M IN! Funnily enough, I actually missed the acceptance phone...

So the last couple of weeks have seen a flurry of discussion in our MBA class Whatsapp group around Brexit, the referendum and currency exchange. Most of us believed...

This highly influential bestseller was first published over 25 years ago. I had wanted to read this book for a long time and I finally got around to it...