GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 29 May 2020, 03:01

### 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

# (8^(1/2) - 1))(1 - 8^(1/2))

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 64240
(8^(1/2) - 1))(1 - 8^(1/2))  [#permalink]

### Show Tags

25 Jul 2018, 22:18
00:00

Difficulty:

5% (low)

Question Stats:

88% (00:59) correct 12% (01:20) wrong based on 46 sessions

### HideShow timer Statistics

$$(\sqrt{8} - 1)(1 - \sqrt{8})$$

A. $$2\sqrt{2} - 9$$

B. $$2\sqrt{2} - 8$$

C. $$4\sqrt{2} - 9$$

D. $$2\sqrt{2}$$

E. $$4\sqrt{2}$$

_________________
MBA Section Director
Affiliations: GMATClub
Joined: 22 May 2017
Posts: 3439
GPA: 4
WE: Engineering (Computer Software)
(8^(1/2) - 1))(1 - 8^(1/2))  [#permalink]

### Show Tags

25 Jul 2018, 22:24
1
$$(\sqrt{8} - 1)(1 - \sqrt{8})$$

=> $$\sqrt{8} - 8 -1 + \sqrt{8}$$

=> $$2\sqrt{8} - 9$$

=> $$4\sqrt{2} - 9$$

Hence option C
_________________
Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4988
Location: India
GPA: 3.5
Re: (8^(1/2) - 1))(1 - 8^(1/2))  [#permalink]

### Show Tags

26 Jul 2018, 10:29
Bunuel wrote:
$$(\sqrt{8} - 1)(1 - \sqrt{8})$$

A. $$2\sqrt{2} - 9$$

B. $$2\sqrt{2} - 8$$

C. $$4\sqrt{2} - 9$$

D. $$2\sqrt{2}$$

E. $$4\sqrt{2}$$

$$(\sqrt{8} - 1)(1 - \sqrt{8})$$

= $$\sqrt{8}(1 - \sqrt{8})- 1(1 - \sqrt{8})$$

= $$\sqrt{8} - 8 - 1 + \sqrt{8}$$

= $$2\sqrt{8} - 9$$

= $$2\sqrt{2^3} - 9$$

= $$4\sqrt{2} - 9$$, Answer must be (C)
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Target Test Prep Representative
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2800
Re: (8^(1/2) - 1))(1 - 8^(1/2))  [#permalink]

### Show Tags

30 Jul 2018, 10:32
Bunuel wrote:
$$(\sqrt{8} - 1)(1 - \sqrt{8})$$

A. $$2\sqrt{2} - 9$$

B. $$2\sqrt{2} - 8$$

C. $$4\sqrt{2} - 9$$

D. $$2\sqrt{2}$$

E. $$4\sqrt{2}$$

FOILing, we have:

√8 - 8 - 1 + √8 = 2√8 - 9 = 2√4 x √2 - 9 = 4√2 - 9

_________________

# Jeffrey Miller

Jeff@TargetTestPrep.com
202 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Re: (8^(1/2) - 1))(1 - 8^(1/2))   [#permalink] 30 Jul 2018, 10:32