It is currently 19 Nov 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

# Quant Questions

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 29 Oct 2010
Posts: 2

Kudos [?]: 3 [0], given: 1

### Show Tags

08 Apr 2011, 10:35
00:00

Difficulty:

(N/A)

Question Stats:

25% (00:00) correct 75% (01:13) wrong based on 4 sessions

### HideShow timer Statistics

For which of the following values of x is √(1-√(2- √x) ) not defined as real number?

A. 1
B. 2
C. 3
D. 4
E. 5

Kudos [?]: 3 [0], given: 1

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1965

Kudos [?]: 2092 [0], given: 376

Re: Quant Questions [#permalink]

### Show Tags

08 Apr 2011, 11:02
Krupa2 wrote:
For which of the following values of x is √(1-√(2- √x) ) not defined as real number?

A. 1
B. 2
C. 3
D. 4
E. 5

$$\sqrt{2-\sqrt{x}} \ge 0$$

$$\sqrt{2-\sqrt{x}} \ge 0$$

Squaring both sides:
$$2-\sqrt{x} \ge 0$$

$$-\sqrt{x} \ge -2$$

Multiplying both sides by -1
$$\sqrt{x} \le 2$$

Squaring both sides:
$$x \le 4$$

x can't be 5 because x should be less than or equal to 4.

Ans: "E"
_________________

Kudos [?]: 2092 [0], given: 376

TOEFL Forum Moderator
Joined: 16 Nov 2010
Posts: 1602

Kudos [?]: 600 [0], given: 40

Location: United States (IN)
Concentration: Strategy, Technology
Re: Quant Questions [#permalink]

### Show Tags

08 Apr 2011, 19:23
The answer is clearly E. If you evaluate the expression, anything that makes 2 - root(x) inside root(2 - root(x)) -ve will make the expression as complex number, hence 5 is the only answer choice that does so, because 2 - root(5) is -ve. The remaining choices still keep the expression as real number.
_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Kudos [?]: 600 [0], given: 40

Manager
Joined: 18 Jan 2011
Posts: 228

Kudos [?]: 37 [0], given: 4

Re: Quant Questions [#permalink]

### Show Tags

08 Apr 2011, 22:26
√(1-√(2- √x) )
if 2- √x is -ive, the result is an imaginary number.
For x=5, 2- √x is -ive
Ans. E
_________________

Good Luck!!!

***Help and be helped!!!****

Kudos [?]: 37 [0], given: 4

Director
Joined: 01 Feb 2011
Posts: 725

Kudos [?]: 146 [0], given: 42

Re: Quant Questions [#permalink]

### Show Tags

14 Apr 2011, 17:21
2-sqrt(x) >=0

-sqrt(x) >= -2

=> x<=4

so cannot be 5.

Kudos [?]: 146 [0], given: 42

Manager
Joined: 18 Jan 2011
Posts: 228

Kudos [?]: 37 [0], given: 4

Re: Quant Questions [#permalink]

### Show Tags

17 Apr 2011, 15:39
fluke wrote:
Krupa2 wrote:

$$\sqrt{2-\sqrt{x}} \ge 0$$

why is this being taken as greater than 0 but not 1
_________________

Good Luck!!!

***Help and be helped!!!****

Kudos [?]: 37 [0], given: 4

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1965

Kudos [?]: 2092 [0], given: 376

Re: Quant Questions [#permalink]

### Show Tags

17 Apr 2011, 16:03
ravsg wrote:
fluke wrote:
Krupa2 wrote:

$$\sqrt{2-\sqrt{x}} \ge 0$$

why is this being taken as greater than 0 but not 1

Square root of a non-negative real number will always be greater than equal to 0. Square root of a negative real number is non-existential.
_________________

Kudos [?]: 2092 [0], given: 376

Re: Quant Questions   [#permalink] 17 Apr 2011, 16:03
Display posts from previous: Sort by

# Quant Questions

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.