Exponents & Roots: Data Sufficiency

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 05 May 2005

Posts: 82

Followers: 1

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

Exponents & Roots: Data Sufficiency [#permalink]

29 Jan 2007, 22:18

How would you solve?

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

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

Director

Joined: 10 Oct 2005

Posts: 732

Location: Madrid

Followers: 3

Kudos [?]: 10 [0], given: 0

Re: Exponents & Roots: Data Sufficiency [#permalink]

29 Jan 2007, 23:02

above720 wrote:

How would you solve?

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

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

I am not sure how to read the question is it
8^a*(1/4)^b=
or
8^(a*(1/4)^b)=

try to solve the first one

8^a*(1/4)^b=
{(1/2)^-3a}*{(1/2)^-2b)}
(1)statement b = 1.5a substitute in original equation
{(1/2)^-3a}*{(1/2)^(-2*1.5a)}=
{(1/2)^-3a}*{(1/2)^(-3a)}=8^2a
2)is clearly insuff
Hence my answer is A
_________________

IE IMBA 2010

Senior Manager

Joined: 19 Jul 2006

Posts: 367

Followers: 1

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

Re: Exponents & Roots: Data Sufficiency [#permalink]

30 Jan 2007, 05:34

above720 wrote:

How would you solve?

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

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

if the question is

8^a * (1/4)^b

= 2^3a * (1/2)^ 2b

(1) b = 1.5a

then 2^3a * (1/2)^ 2b = 2^3a * (1/2) ^ 3a =1

Ans = A

if the question is 8^[a(1/4)]^b
then Ans= C

SVP

Joined: 05 Jul 2006

Posts: 1562

Followers: 4

Kudos [?]: 63 [0], given: 32

[#permalink]

30 Jan 2007, 07:21

How would you solve?

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

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

8^a(1/4)^b= = 2^3a * 2^-2b = 2^3a -2 b

from one

THE EXPRESSION IS DOWN TO 2^0 = 1......SUFF

from two

no info about value of b.......not suff

ANSWER IS INDEED A , THANKS SUMITHRA

Last edited by yezz on 30 Jan 2007, 07:31, edited 1 time in total.

SVP

Joined: 05 Jul 2006

Posts: 1562

Followers: 4

Kudos [?]: 63 [0], given: 32

[#permalink]

30 Jan 2007, 07:30

SUMITHRA , THANKS MAN U R RIGHT

I FORGOT THE CRAZY 2

ANSWER IS THUS A

Senior Manager

Joined: 01 Feb 2005

Posts: 275

Followers: 1

Kudos [?]: 18 [0], given: 1

[#permalink]

30 Jan 2007, 07:31

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

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

(8^a)(1/4)^b
Subsitute b from 1

(8)^a(1/4)^1.5a

This an example of (a)^x (b)^x. Cannot be solved. Hence B, C, E

From 2 it is not possible to find a value of the equation. Hence C, E
Combining 1 and 2

You can easily find the value of the equation. Hence C is the best answer

Senior Manager

Joined: 24 Oct 2006

Posts: 348

Followers: 1

Kudos [?]: 10 [0], given: 0

[#permalink]

30 Jan 2007, 08:53

yezz wrote:

SUMITHRA , THANKS MAN U R RIGHT

I FORGOT THE CRAZY 2

ANSWER IS THUS A

You are welcome.

Guess, you just need to relax before the big day.

You'll do fine. All the best.

[#permalink] 30 Jan 2007, 08:53

		Similar topics	Author	Replies	Last post
Similar Topics:		Data sufficiency roots question	apollo168	6	27 Jul 2006, 08:48
		Data Sufficiency	rbcola	2	14 Aug 2006, 12:50
		data sufficiency	Zaur	5	03 Jul 2008, 04:43
		data sufficiency	Zaur	3	03 Jul 2008, 05:09
	1	VeritasPrep blogpost: GMAT Data Sufficiency Powers and Roots	v1gnesh	4	01 May 2013, 19:29

Exponents & Roots: Data Sufficiency

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

Exponents & Roots: Data Sufficiency

Exponents & Roots: Data Sufficiency

Main navigation

GMAT Resources

Partners

MBA Resources