Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 22 May 2017, 19:29

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A Simple but confusing DS [ 8^a(1/4)^b = ? ]

Author Message
Intern
Joined: 09 Oct 2008
Posts: 18
Followers: 0

Kudos [?]: 2 [0], given: 0

A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 01:43
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

8^a(1/4)^b = ?

(1) b = 1.5a
(2) a = 2

Lets see how you guys solve it
Intern
Joined: 24 Jun 2007
Posts: 28
Followers: 1

Kudos [?]: 3 [0], given: 0

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 02:08
8^a(1/4)^b = ?
2^3a 2^-2b = ?
so 2^(3a-2b) = ?

(S1) b = 1.5a

then 2^ (3a - 2(1.5a)) = ?
2^ (3a-3a) =?
2^0= 1......Suff

(S2) a = 2
2^(3(2) - 2b) =?
still stuck with b .....then ...insuff

my thought is A
Intern
Joined: 09 Oct 2008
Posts: 18
Followers: 0

Kudos [?]: 2 [0], given: 0

### Show Tags

17 Oct 2008, 02:23
You are right paeagain.. the OA is (A)

But whats confusing me, upon solving we end up with:

8^a.(1/4)^b

2^(3a).2^(-2b)

3a-2b = ?

But isn't it same as the S(1) itself:

b = 1.5a
2b = 3a

and if we further see our original equation 3a-2b = ?
it tells us 3a = 2b which is what the statement (1) is. So is it solving the question.
I know how you will explain this as 3a-2b= 0 so its sufficient but that is exactly the same as question stem.
VP
Joined: 30 Jun 2008
Posts: 1034
Followers: 14

Kudos [?]: 612 [0], given: 1

### Show Tags

17 Oct 2008, 04:25
alive wrote:
You are right paeagain.. the OA is (A)

But whats confusing me, upon solving we end up with:

8^a.(1/4)^b

2^(3a).2^(-2b)

3a-2b = ?

But isn't it same as the S(1) itself:

b = 1.5a
2b = 3a

and if we further see our original equation 3a-2b = ?
it tells us 3a = 2b which is what the statement (1) is. So is it solving the question.
I know how you will explain this as 3a-2b= 0 so its sufficient but that is exactly the same as question stem.

This is a C-Trap question. Search this forum for more details on C-Trap.

The question asks what is the value of 3a-2b.

Statement 1 says the value of 3a-2b is zero.

You will come across such questions .... like is x=0? and one of the statements will be like x^2 + y^2 = 0 which clearly says x=0. It may sound simple, but many people like me will fail to see the logic and fall for the C-Trap.
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Senior Manager
Joined: 21 Apr 2008
Posts: 269
Location: Motortown
Followers: 2

Kudos [?]: 150 [0], given: 0

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 04:57
I don't know whether I would think about C-Traps etc., but
2^(3a -2b) = ?

from statement 1 :
3a = 2b
2^(2b-2b) = 2^0 = 1

from statement 2:
a= 2 - won't help
VP
Joined: 30 Jun 2008
Posts: 1034
Followers: 14

Kudos [?]: 612 [0], given: 1

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 05:27
LiveStronger wrote:
I don't know whether I would think about C-Traps etc., but
2^(3a -2b) = ?

from statement 1 :
3a = 2b
2^(2b-2b) = 2^0 = 1

from statement 2:
a= 2 - won't help

Don't have to think about it Knowing doesn't hurt ....
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Senior Manager
Joined: 21 Apr 2008
Posts: 269
Location: Motortown
Followers: 2

Kudos [?]: 150 [0], given: 0

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 06:37
Good one

Btw, can you explain more about C- Traps ?
VP
Joined: 30 Jun 2008
Posts: 1034
Followers: 14

Kudos [?]: 612 [1] , given: 1

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ] [#permalink]

### Show Tags

17 Oct 2008, 07:02
1
KUDOS
LiveStronger wrote:
Good one

Btw, can you explain more about C- Traps ?

Check this one first --- LONG ONE ---- viewtopic.php?t=34329
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Re: A Simple but confusing DS [ 8^a(1/4)^b = ? ]   [#permalink] 17 Oct 2008, 07:02
Display posts from previous: Sort by