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

 It is currently 21 Oct 2018, 19:11

### 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

# Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Senior Manager
Joined: 26 Jul 2005
Posts: 304
Location: Los Angeles
Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

27 Oct 2005, 16:35
1
00:00

Difficulty:

(N/A)

Question Stats:

75% (02:35) correct 25% (01:34) wrong based on 4 sessions

### HideShow timer Statistics

Is x/m(m^2 + n^2 + k^2) = xm + yn + zk?

(1) z/k = x/m
(2) x/m = y/n

OPEN DISCUSSION OF THIS QUESTION IS HERE: is-x-m-m-2-n-2-k-2-xm-yn-zk-99423.html

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Manager
Joined: 20 Mar 2005
Posts: 200
Location: Colombia, South America
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

27 Oct 2005, 16:49
I think is C

x/m(m^2 + n^2 + z^2) = xm + yn + zk

that is equal to

xm + xn^2/m + xz^2/n = xm + yn + zk

from I: x/m = y/n then xn = ym and from there (xn*n)/m is equal to
ym*n/m equal to yn

so insuff

from ii, do the same stuff as i and you get zk

so insuff

taking both it works so C
Senior Manager
Joined: 26 Jul 2005
Posts: 304
Location: Los Angeles
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

28 Oct 2005, 15:54
Right again - OA is C.
Intern
Joined: 14 Sep 2010
Posts: 19
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

18 Nov 2011, 03:39
Is x/m(m^2 + n^2+ k^2) = xm + yn + zk?

xm^2 + xn^2 + xk^2 = xmm +ynm +zkm?

Is xn^2 + xk^2 = ynm + zkm?

(1) z/k = x/m (xk = mz)

xk^2 = (xk)k = (mzk)

xn^2 + xk^2 = ynm + zkm =

xn^2 = ynm?
xn = my?

(2) x/m = y/n (xn = my)

xn^2 = (xn)n = (my)n

xn^2 + xk^2 = ynm + zkm =

xk^2 = zkm?
xk = mz?

Put (1) and (2) together

xn^2 + xk^2 = ynm + zkm =

(my)n + (mz)k = ynm + zkm

Both statements used = Answer C

Posted from my mobile device
Manager
Joined: 13 May 2011
Posts: 245
WE 1: IT 1 Yr
WE 2: Supply Chain 5 Yrs
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

18 Nov 2011, 05:19
is xm^2+xn^2+xk^2=xm^2+ynm+zkm
i. e. xn^2+xk^2=ynm+zkm
statement 1: xk=zm
xn^2=ynm Not Sufficient
Statement 2: ym=xn
xk^2=zkm Not Sufficient
Together: xn^2+xk^2=xn^2+xk^2
Sufficient
Math Expert
Joined: 02 Sep 2009
Posts: 50009
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)  [#permalink]

### Show Tags

23 Nov 2017, 07:43
Is $$\frac{x}{m}*(m^2+n^2+k^2)=xm+yn+zk$$?

Multiply both part by $$m$$, to get rid of fraction part and open the brackets: is $$xm^2+xn^2+xk^2=xm^2+ynm+zkm$$?

$$xm^2$$ will cancel out and the question becomes: is $$xn^2+xk^2=ynm+zkm$$?

(1) $$\frac{z}{k}=\frac{x}{m}$$ --> $$zm=kx$$ --> substitute zm with kx --> is $$xn^2+xk^2=ynm+xk^2$$ --> $$xk^2$$ will cancel out and the question becomes is "$$xn^2=ynm$$?" Not sufficient.

(2) $$\frac{x}{m}=\frac{y}{n}$$ --> $$xn=ym$$ --> substitute ym with xn --> is $$xn^2+xk^2=xn^2+zkm$$ --> $$xn^2$$ will cancel out and the question becomes "is $$xk^2=zkm$$?" Not sufficient.

(1)+(2) is $$xn^2+xk^2=ynm+zkm$$? --> substitutein from (1) and (2) --> is $$xn^2+xk^2=xn^2+xk^2$$? Answer is YES. Sufficient.

OPEN DISCUSSION OF THIS QUESTION IS HERE: is-x-m-m-2-n-2-k-2-xm-yn-zk-99423.html

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________
Re: Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2) &nbs [#permalink] 23 Nov 2017, 07:43
Display posts from previous: Sort by

# Is x/m(m^2 + n^2 + k^2) = xm + yn + zk? (1) z/k = x/m (2)

 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®.