Last visit was: 11 Sep 2024, 06:55 It is currently 11 Sep 2024, 06:55
Toolkit
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

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.

# Is 8^x > 4^y? (1) x > y (2) 3x > 2y

SORT BY:
Tags:
Show Tags
Hide Tags
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 10131
Own Kudos [?]: 17263 [22]
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6803
Own Kudos [?]: 31266 [12]
Given Kudos: 799
General Discussion
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 10131
Own Kudos [?]: 17263 [0]
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Board of Directors
Joined: 17 Jul 2014
Posts: 2142
Own Kudos [?]: 1203 [1]
Given Kudos: 236
Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30
GPA: 3.92
WE:General Management (Transportation)
Re: Is 8^x > 4^y? (1) x > y (2) 3x > 2y [#permalink]
1
Kudos
MathRevolution wrote:
Is 8^x>4^y?

1) x>y
2) 3x>2y

* A solution will be posted in two days.

the question can be rewritten as:
2^3x > 2^2y?
or the real question:
3x>2y?

tricky one...almost selected D, but remembered that x and y can be negative as well..

1. x>y. if both numbers are positive, then it is sufficient.
if x=-5, y=-6
x>y
but:
3*-5 = -15
2*-6 = -12
3x<2y
since there are different outcomes, 1 alone is insufficient.

2. exactly says what we need - sufficient.

RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11513
Own Kudos [?]: 35934 [0]
Given Kudos: 333
Re: Is 8^x > 4^y? (1) x > y (2) 3x > 2y [#permalink]
dramamur wrote:
Is $$8^x$$ > $$4^y$$ ?

1) x > y
2) 3x > 2y

$$8^x>4^y.....2^{3x}>2^{2y}$$...
so Q basically asks if 3x>2y...

lets see the statements..

1) x > y
x>2y...YES
x=1.1y...NO
Insuff

2) 3x > 2y
sufficient as this is what we are looking for

B
CEO
Joined: 26 Feb 2016
Posts: 2863
Own Kudos [?]: 5406 [0]
Given Kudos: 47
Location: India
GPA: 3.12
Re: Is 8^x > 4^y? (1) x > y (2) 3x > 2y [#permalink]
$$8^x = 2^{3x}$$
$$4^y = 2^{2y}$$
In essence, we have been asked to test if $$2^{3x} > 2^{2y}$$

1. x > y
If x = 2 and y = 1 then $$2^6 > 2^2$$
But if x = -3 and y = -4, then $$2^{-9} < 2^{-8}$$(Insufficient)

2. 3x > 2y
This is enough to determine that $$2^{3x} > 2^{2y}$$ is always true.(Sufficient) (Option B)
Non-Human User
Joined: 09 Sep 2013
Posts: 34814
Own Kudos [?]: 876 [0]
Given Kudos: 0
Re: Is 8^x > 4^y? (1) x > y (2) 3x > 2y [#permalink]
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.
Re: Is 8^x > 4^y? (1) x > y (2) 3x > 2y [#permalink]
Moderator:
Math Expert
95450 posts