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:

Operation F means “take the square root,” operation G means [#permalink]

Show Tags

19 Apr 2013, 23:56

5

This post received KUDOS

3

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

67% (02:29) correct
33% (01:27) wrong based on 153 sessions

HideShow timer Statistics

Operation F means “take the square root,” operation G means “multiply by constant c,” and operation H means “take the reciprocal.” For which value of c is the result of applying the three operations to any positive x the same for all of the possible orders in which the operations are applied?

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

20 Apr 2013, 00:16

1

This post received KUDOS

emmak wrote:

Operation F means “take the square root,” operation G means “multiply by constant c,” and operation H means “take the reciprocal.” For which value of c is the result of applying the three operations to any positive x the same for all of the possible orders in which the operations are applied?

(A) –1

(B) –½

(C) 0

(D) ½

(E) 1

Express appreciation by pressing KUDOS.

Ok. Looking at options will give you what we are looking at. A and B are out because square root will always be positive. So, we are not dealing with negative numbers. C is out because of 1/0 --> infinity. We can check D and E. E satisfy in first shot.
_________________

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

06 May 2013, 22:25

1

This post received KUDOS

assume that all the operations give a constant answer "k". take 1st order for eg. HGF which gives sqroot{c/x} = k 2nd order eg. HFG which gives c*sqroot{1/x} = k

Therefore, sqr{c/x} = c*sqr{1/x} this gives, c = sqr{c} => sqr{c} = 1 => c = 1

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

06 May 2013, 23:36

1

This post received KUDOS

I approached this question by going through the answers. The value of C changes with values in the option A,B,C,D when different combination is applied. The value of E stands out in any operation, the value remains same whether it is multiplication or division. E is the answer strainght away.

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

07 May 2013, 01:22

1

This post received KUDOS

1

This post was BOOKMARKED

In such a problem, we should consider an example. For instance, x = 2.

Considering the operations we have :

- F : square root ; - G : multiply by a constant c ; - H : reciprocal ;

We want to know which value of the constant "c" that would allow us to get the same result no matter the order of operations applied. Since we have three operations, we get to have 6 possibilities (to be even more accurate 3! = 6) :

F - G - H : \(\frac{1}{c*\sqrt{2}}\) F - H - G : \(\frac{c}{\sqrt{2}}\) G - F - H : \(\frac{1}{\sqrt{2*c}}\) G - H - F : \(\sqrt{\frac{1}{2*c}}\) H - F - G : \(c*\sqrt{\frac{1}{2}}\) H - G - F : \(\sqrt{\frac{c}{2}}\)

As you can see, there are instances where the constant c is within a square root, or in the denominator of a fraction. Which means that zero and non-zero negative values can't be considered, therefore answers A, B and C are excluded.

Answer choice D is a fraction and seeing as the constant c can be either in the numerator or the denominator of the resulting fraction, c can either become \(\frac{1}{2}\) or 2. Which means we get different values everytime we change the order of the operations. Therefore, answer choice D is excluded as well.

Finally, we're left with one possible answer, E, which gives us \(c = 1\).

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

07 May 2013, 16:43

Operation F means “take the square root,” operation G means “multiply by constant c,” and operation H means “take the reciprocal.” For which value of c is the result of applying the three operations to any positive x the same for all of the possible orders in which the operations are applied?

(A) –1

(B) –½

(C) 0

(D) ½

(E) 1

it is simple if we work our way from answer choices

A) if we multiplied c=-1 by x in one of the operations .. there exist no real square root...out b) same with the -ve sign like above ..........out c) there is no reciprocal for x when multiplied by zero i ..out d) just try 2 orders (c : x/2 ,f: sqrt x/2 , h: sqrt x/2) (sqrtx , 2sqrtx 1/2 sqrt x)...out E) ... the only one left intact ... bingo

Re: Operation F means “take the square root,” operation G means [#permalink]

Show Tags

22 Aug 2015, 18:16

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.
_________________

Happy New Year everyone! Before I get started on this post, and well, restarted on this blog in general, I wanted to mention something. For the past several months...

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Happy 2017! Here is another update, 7 months later. With this pace I might add only one more post before the end of the GSB! However, I promised that...

The words of John O’Donohue ring in my head every time I reflect on the transformative, euphoric, life-changing, demanding, emotional, and great year that 2016 was! The fourth to...