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:

Official Answer and Stats are available only to registered users. Register/Login.

_________________

Encourage me by pressing the KUDOS if you find my post to be helpful.

Help me win "The One Thing You Wish You Knew - GMAT Club Contest" http://gmatclub.com/forum/the-one-thing-you-wish-you-knew-gmat-club-contest-140358.html#p1130989

Last edited by dvinoth86 on 19 Feb 2012, 17:39, edited 1 time in total.

(1) x^2 > y. Clearly insufficient: if x=2 and y=3 then the answer is NO but if x=2 and y=1 then the answer is YES.

(2) √x < y. Also insufficient: if x=4 and y=5 then the answer is NO but if x=4 and y=3 then the answer is YES. Notice that since x is under the square root sign then it must be true that \(x\geq{0}\).

(1)+(2) \(\sqrt{x}<y<x^2\) --> both \(x\) and \(y\) are between \(\sqrt{x}\) and \(x^2\), but we can not say which one is greater. Not sufficient. For example: if \(x=y=4\) (\(\sqrt{4}<4<4^2\)) then the answer is NO but if \(x=4\) and \(y=3\) (\(\sqrt{4}<3<4^2\)) then the answer is YES. Not sufficient.

(1) x^2 > y. Clearly insufficient: if x=2 and y=3 then the answer is NO but if x=2 and y=1 then the answer is YES. (2) √x < y. Also insufficient: if x=4 and y=5 then the answer is NO but if x=4 and y=3 then the answer is YES. Notice that since x is under the square root sign then it must be true that \(x\geq{0}\).

(1)+(2) \(\sqrt{x}<y<x^2\) --> both \(x\) and \(y\) are between \(\sqrt{x}\) and \(x^2\), but we can not say which one is greater. Not sufficient. For example: if \(x=y=4\) (\(\sqrt{4}<4<4^2\)) then the answer is NO but if \(x=4\) and \(y=3\) (\(\sqrt{4}<3<4^2\)) then the answer is YES. Not sufficient.

Answer: E.

Hope it's clear.

Its not always possible to take examples like you have shown for each statement. I mean sometimes the variable values just doesn't fit. Solving it by use of abstract maths is tough.

Ho do we tackle this situation. Do we have a strategy on how to pick numbers faster for testing.

(1) x^2 > y. Clearly insufficient: if x=2 and y=3 then the answer is NO but if x=2 and y=1 then the answer is YES. (2) √x < y. Also insufficient: if x=4 and y=5 then the answer is NO but if x=4 and y=3 then the answer is YES. Notice that since x is under the square root sign then it must be true that \(x\geq{0}\).

(1)+(2) \(\sqrt{x}<y<x^2\) --> both \(x\) and \(y\) are between \(\sqrt{x}\) and \(x^2\), but we can not say which one is greater. Not sufficient. For example: if \(x=y=4\) (\(\sqrt{4}<4<4^2\)) then the answer is NO but if \(x=4\) and \(y=3\) (\(\sqrt{4}<3<4^2\)) then the answer is YES. Not sufficient.

Answer: E.

Hope it's clear.

Its not always possible to take examples like you have shown for each statement. I mean sometimes the variable values just doesn't fit. Solving it by use of abstract maths is tough.

Ho do we tackle this situation. Do we have a strategy on how to pick numbers faster for testing.

First of all: on DS questions when plugging numbers, goal is to prove that the statement is not sufficient. So we should try to get a YES answer with one chosen number(s) and a NO with another.

Now, number picking strategy can vary for different problems. Generally it's good to test negative/positive/zero as well as integer/fraction to get a YES and a NO answers. If you deal with two variables it's also helpful to test x<y and x>y in addition to the former.

As for this question: you don't really need to test the numbers for it, I just used them to demonstrate that the statements are not sufficient.

From (1)+(2): we have that \(\sqrt{x}<y<x^2\). Both \(x\) and \(y\) are between \(\sqrt{x}\) and \(x^2\) (\(x\) is between them because \(\sqrt{x}<x^2\), which means that \(x>1\)): \(\sqrt{x}\)------\(x\)------\(x^2\), now \(y\) can be in the green range (answer YES) as well in the red range (answer NO). So, we can not say whether x>y.

Can anyone explain a simple method to this could not follovv statement B

\

Bunuel if you can help please

1) Statement 1 only tells us that x is positive and nothing else. So insufficient

2) Statement 2 wants us to go through the process of squaring both sides to make the equation x<y^2, but we do not know anything about the sign so basically it would look like:

Can anyone explain a simple method to this could not follovv statement B

(1) For \(x=-2 > y=-3, \, x^2=4>-3.\) But \(x=2 < y=3\), although \(x^2=4>y=3.\) Not sufficient.

(2) From the given inequality it follows that \(x\) must be non-negative (because of the square root) and since \(y>\sqrt{x}\geq0\), necessarily \(y\) is positive. Therefore, we can square the given inequality and get \(x<y^2.\)

For \(x=4, y=3, \,x=4<y^2=9,\) and \(x>y.\) But if \(y=1,\) we cannot have simultaneously \(x<y^2=1\) and \(x>y=1.\) Not sufficient.

(1) and (2) together: Consider the two cases: \(x=2, y=3\) and \(x=4,y=3.\) Again, not sufficient.

Answer E.
_________________

PhD in Applied Mathematics Love GMAT Quant questions and running.

Last edited by EvaJager on 18 Aug 2012, 22:04, edited 1 time in total.

Can anyone explain a simple method to this could not follovv statement B

\

Bunuel if you can help please

1) Statement 1 only tells us that x is positive and nothing else. So insufficient

2) Statement 2 wants us to go through the process of squaring both sides to make the equation x<y^2, but we do not know anything about the sign so basically it would look like:

x^2 > y

and combined,

x<y^2 or x>y^2

x^2 > y

(2) We know about the signs: \(x\) must be non-negative, otherwise the square root is not defined. Also, because the square root is non-negative, \(y\) must be positive. Therefore, in this case we can square the given inequality and obtain \(x<y^2.\)
_________________

PhD in Applied Mathematics Love GMAT Quant questions and running.

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.
_________________

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.
_________________