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:

ywilfred's explanation covers what I did but here's just detailed breakdown:

-from the stem, we know X and Y are positive so we only need to test pos numbers

(A) Y= 2X

-from this, we know Y is twice X. I used (x=1,y=2) and(x=2,y=4). You can select any number so long as it fits (A). (x=5,y=10) etc. But small numbers are easier to work with.

Quote:

A) If x = 1, y = 2, then 4(1/9) < 1 If x = 2, y = 4, then 16(1/81) < 1

A is sufficient

Now the only possible choices are A and D.

(B) Y=4

-this says nothing about X so it's insufficient

Answer is A.

The logic you are following (two unknowns require two equations) doesn't apply here because we're not asked to find a specific value for either X or Y. We only need to know if

(4^X) (1/3)^Y < 1

And from (A), we know that the left side of this inequality will always be less than 1.