Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 02 Sep 2015, 19:21

### 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

# Is x/p(p 2 + q 2 + r 2 ) = x

Author Message
TAGS:
Moderator
Joined: 01 Sep 2010
Posts: 2654
Followers: 512

Kudos [?]: 3963 [0], given: 727

Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  03 Feb 2013, 17:45
Expert's post
2
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

76% (02:51) correct 24% (02:18) wrong based on 58 sessions
Is $$\frac{x}{p}$$ $$(p^2 + q^2 + r^2 ) = xp + yq + zr$$?

(1) $$q^2 = r^2$$

(2) $$yq = zr$$
[Reveal] Spoiler: OA

_________________
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 5867
Location: Pune, India
Followers: 1483

Kudos [?]: 7989 [1] , given: 190

Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  03 Feb 2013, 21:46
1
KUDOS
Expert's post
carcass wrote:
Is $$\frac{x}{p}$$ $$(p 2 + q 2 + r 2 ) = xp + yq + zr$$?

(1) $$q^2 = r^2$$

(2) $$yq = zr$$

There are too many variables here so let's focus on logic.

Is $$\frac{x}{p}$$ $$(p 2 + q 2 + r 2 ) = xp + yq + zr?$$
Is $$xp + \frac{x}{p}(q 2 + r 2 ) = xp + yq + zr?$$
Is $$\frac{x}{p}(q 2 + r 2 ) = yq + zr?$$

(1) $$q^2 = r^2$$
Even if q^2 = r^2, there are lots of other variables e.g. x, y and z which can take different values to make the two sides unequal. But if q = r = 0, the two sides become equal so not sufficient alone.

(2) $$yq = zr$$
Again, there are no constraints on x and p and they can take different values to make the two sides of the equation unequal. But if q = r = 0, the two sides become equal so not sufficient alone.

Using both together, there are still no constraints on the values x and p can take so the two sides needn't be equal. But if q = r = 0, the two sides become equal so not sufficient.

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

Moderator
Joined: 01 Sep 2010
Posts: 2654
Followers: 512

Kudos [?]: 3963 [0], given: 727

Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  04 Feb 2013, 03:59
Expert's post
i thought E as well but I wanted to be sure

Thanks the question was a bit convoluted
_________________
Moderator
Joined: 10 May 2010
Posts: 824
Followers: 22

Kudos [?]: 351 [0], given: 192

Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  04 Feb 2013, 13:16
What additional condition must be present for the equation to be true ?

[Reveal] Spoiler:
$$xq = yp$$

_________________

The question is not can you rise up to iconic! The real question is will you ?

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 6190
Followers: 345

Kudos [?]: 70 [0], given: 0

Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  13 Jan 2015, 12:39
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.
_________________
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 3497
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Followers: 148

Kudos [?]: 936 [0], given: 57

Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]  13 Jan 2015, 12:56
Expert's post
Hi All,

DS questions rarely involve this many variables, but when a DS question is this "crazy looking" the solution can usually be found by TESTing VALUES and keeping everything really 'simple'

Here, we're asked if (X/P)(P^2 + Q^2 + R^2) = XP + YQ + ZR. This is a YES/NO question.

The first thing that you should notice is that the variables Y and Z only appear on the right side of the equation/question. Their respective values will have a great impact on whether the answer to the question is YES or NO.

Fact 1: Q^2 = R^2

Let's TEST VALUES (and keep it simple!)

IF....
EVERY variable = 0, then the answer to the question is YES.

IF.....
X, P, Q and R = 1
Y = Z = 2, then the answer to the question is NO.
Fact 1 is INSUFFICIENT

Fact 2: YQ = ZR

Notice how BOTH TESTs from Fact 1 ALSO fit Fact 2.....This gives us a YES answer and a NO answer here as well.
Fact 2 is INSUFFICIENT

Combined, we have the same two TESTs that fit BOTH Facts and provide 2 different answers.
Combined, INSUFFICIENT

[Reveal] Spoiler:
E

GMAT assassins aren't born, they're made,
Rich
_________________

Re: Is x/p(p 2 + q 2 + r 2 ) = x   [#permalink] 13 Jan 2015, 12:56
Similar topics Replies Last post
Similar
Topics:
Is x/p (p2+q2+r2) = xp+yq+zr? 2 17 Jul 2015, 19:24
If r = q^2 and r does not equal 0, is r > q? 2 08 May 2015, 07:36
2 If p, q, r, and s are nonzero numbers, is (p – 1)(q - 2)^2(r – 3)^3(s 3 12 Dec 2014, 06:29
Is rs=rx-2? 1. r is odd 2. x=s+2 2 17 May 2010, 12:44
Is 1/p>r/(r^2+2)? 4 17 Jun 2008, 17:44
Display posts from previous: Sort by