It is currently 10 Dec 2017, 17:38

### 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:

### Hide Tags

Board of Directors
Joined: 01 Sep 2010
Posts: 3409

Kudos [?]: 9448 [0], given: 1185

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

### Show Tags

03 Feb 2013, 18:45
2
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

75% (02:47) correct 25% (02:18) wrong based on 93 sessions

### HideShow timer Statistics

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

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

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

_________________

Kudos [?]: 9448 [0], given: 1185

Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7784

Kudos [?]: 18090 [1], given: 236

Location: Pune, India
Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink]

### Show Tags

03 Feb 2013, 22:46
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 Kudos [?]: 18090 [1], given: 236 Board of Directors Joined: 01 Sep 2010 Posts: 3409 Kudos [?]: 9448 [0], given: 1185 Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink] ### Show Tags 04 Feb 2013, 04:59 i thought E as well but I wanted to be sure Thanks the question was a bit convoluted _________________ Kudos [?]: 9448 [0], given: 1185 Retired Moderator Joined: 10 May 2010 Posts: 823 Kudos [?]: 440 [0], given: 192 Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink] ### Show Tags 04 Feb 2013, 14:16 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 ? Kudos [?]: 440 [0], given: 192 Non-Human User Joined: 09 Sep 2013 Posts: 14956 Kudos [?]: 287 [0], given: 0 Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink] ### Show Tags 13 Jan 2015, 13:39 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. _________________ Kudos [?]: 287 [0], given: 0 EMPOWERgmat Instructor Status: GMAT Assassin/Co-Founder Affiliations: EMPOWERgmat Joined: 19 Dec 2014 Posts: 10351 Kudos [?]: 3661 [0], given: 173 Location: United States (CA) GMAT 1: 800 Q51 V49 GRE 1: 340 Q170 V170 Re: Is x/p(p 2 + q 2 + r 2 ) = x [#permalink] ### Show Tags 13 Jan 2015, 13:56 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 Final Answer: [Reveal] Spoiler: E GMAT assassins aren't born, they're made, Rich _________________ 760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com # Rich Cohen Co-Founder & GMAT Assassin Special Offer: Save$75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Kudos [?]: 3661 [0], given: 173

Re: Is x/p(p 2 + q 2 + r 2 ) = x   [#permalink] 13 Jan 2015, 13:56
Display posts from previous: Sort by