GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 20 Oct 2019, 02:03

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

If non-zero x is the reciprocal of y, then which of the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
User avatar
Joined: 21 Oct 2013
Posts: 411
If non-zero x is the reciprocal of y, then which of the  [#permalink]

Show Tags

New post 02 Mar 2014, 12:22
1
8
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

65% (02:12) correct 35% (02:09) wrong based on 167 sessions

HideShow timer Statistics

If non-zero x is the reciprocal of y, then which of the following may be true?

A. x / (1/y) = 0.5
B. (1/x) / y = 2
C. (1/y) / x = 0.5
D. (1/x)/(1/y) = 0.5
E. y/(1/x) = 2

Hi, can anyone explain this, please.
NOTE: Reciprocal of x = 1/x
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9704
Location: Pune, India
Re: If non-zero x is the reciprocal of y, then which of the  [#permalink]

Show Tags

New post 02 Mar 2014, 22:54
1
3
goodyear2013 wrote:
If non-zero x is the reciprocal of y, then which of the following may be true?
x / (1/y) = 0.5
(1/x) / y = 2
(1/y) / x = 0.5
(1/x)/(1/y) = 0.5
y / (1/x) = 2

Hi, can anyone explain this, please.
NOTE: Reciprocal of x = 1/x


Given: x = 1/y
then xy = 1
Also, 1/xy = 1

Now look at the options:
(A) x / (1/y) = 0.5 => xy = 0.5 (Not possible. We know xy = 1)

(B) (1/x) / y = 2 => 1/(xy) = 2 (Not possible. We know 1/xy = 1)

(C) (1/y) / x = 0.5 => 1/yx = 0.5 (Not possible. We know 1/xy = 1)

(D) (1/x)/(1/y) = 0.5

(E) y / (1/x) = 2 => yx = 2 (Not possible. We know xy = 1)

Only option (D) is possible.
(1/x)/(1/y) = 0.5
y/x = 1/2
When \(x = \sqrt{2}, y = 1/\sqrt{2}\), xy = 1, 1/xy = 1 and y/x = 1/2. So option (D) is possible.
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58443
Re: If non-zero x is the reciprocal of y, then which of the  [#permalink]

Show Tags

New post 03 Mar 2014, 00:18
2
goodyear2013 wrote:
If non-zero x is the reciprocal of y, then which of the following may be true?

A. x / (1/y) = 0.5
B. (1/x) / y = 2
C. (1/y) / x = 0.5
D. (1/x)/(1/y) = 0.5
E. y/(1/x) = 2

Hi, can anyone explain this, please.
NOTE: Reciprocal of x = 1/x


Notice that the question asks which of the following COULD be true, not MUST be true.

x is the reciprocal of y means that x=1/y (y=1/x). Now, replace 1/x by y or 1/y by x in the options:

A. x/(1/y) = 0.5 --> x/x = 0.5 --> 1 = 0.5. WRONG.

B. (1/x)/y = 2 --> y/y = 2 --> 1 = 2. WRONG.

C. (1/y)/x = 0.5 --> x/x = 0.5 --> 1 = 0.5. WRONG.

D. (1/x)/(1/y) = 0.5 --> (1/x)/x = 1/2 --> 1/x^2 = 1/2 --> x^2 = 2. Well, this is possible, if \(x=\sqrt{2}\) or \(x=-\sqrt{2}\).

E. y/(1/x) = 2 --> y/y = 2 --> 1 = 2. WRONG.

Answer: D.

Hope it's clear.
_________________
SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1749
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If non-zero x is the reciprocal of y, then which of the  [#permalink]

Show Tags

New post 05 Mar 2014, 22:34
In all the options, replace \(\frac{1}{x} = y\) OR \(\frac{1}{y} = x\) (as applicable) so that fraction is removed:

A: 1 = 0.5 (Wrong)

B: 1 = 2 (Wrong)

C: 1 = 0.5 (Wrong)

E: 1 = 2 (WRONG)

D:

\(\frac{1}{x^2} = 0.5\)

\(x^2 = 2\)

\(x = \sqrt{2} ; y = \frac{1}{\sqrt{2}}\)

Answer = D
_________________
Kindly press "+1 Kudos" to appreciate :)
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13293
Re: If non-zero x is the reciprocal of y, then which of the  [#permalink]

Show Tags

New post 24 Jul 2019, 22:08
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.
_________________
GMAT Club Bot
Re: If non-zero x is the reciprocal of y, then which of the   [#permalink] 24 Jul 2019, 22:08
Display posts from previous: Sort by

If non-zero x is the reciprocal of y, then which of the

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





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne