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• ### $450 Tuition Credit & Official CAT Packs FREE November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth$100 with the 3 Month Pack ($299) • ### Free GMAT Strategy Webinar November 17, 2018 November 17, 2018 07:00 AM PST 09:00 AM PST Nov. 17, 7 AM PST. Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT. # The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics Author Message TAGS: ### Hide Tags Math Revolution GMAT Instructor Joined: 16 Aug 2015 Posts: 6504 GMAT 1: 760 Q51 V42 GPA: 3.82 The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value [#permalink] ### Show Tags 05 Sep 2018, 01:16 00:00 Difficulty: 5% (low) Question Stats: 82% (00:50) correct 18% (00:39) wrong based on 65 sessions ### HideShow timer Statistics [Math Revolution GMAT math practice question] The numbers $$x, y$$ and $$z$$ are in the ratio $$3$$ to $$4$$ to $$5$$. What is the value of $$x$$? 1) $$y = 16$$ 2) The difference between $$y$$ and $$z$$ is $$4$$ _________________ MathRevolution: Finish GMAT Quant Section with 10 minutes to spare The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy. "Only$99 for 3 month Online Course"
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Re: The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value  [#permalink]

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05 Sep 2018, 01:33
MathRevolution wrote:
[Math Revolution GMAT math practice question]

The numbers $$x, y$$ and $$z$$ are in the ratio $$3$$ to $$4$$ to $$5$$. What is the value of $$x$$?

1) $$y = 16$$
2) The difference between $$y$$ and $$z$$ is $$4$$

We know the ratio x:y:z=3:4:5=3a:4a:5a
So if we know any one value, we can find all

1) y=16
So 4a=16....a=4
x=3a=4*3=12
Sufficient

2) z-y=4
So 5a-4a=4....a=4
So x=3a=3*4=12...
But is it possible that 4a-5a=4...a=-4 and thus 3a=-12
NO, because generally on GMAT, the ratios are of positive quantity
So only one value 12
Sufficient

D
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Re: The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value  [#permalink]

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07 Sep 2018, 00:16
=>

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method I s the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question.

The original condition gives the proportion $$x : y : z = 3 : 4 : 5$$, so we can write $$x = 3k, y = 4k$$ and $$z = 5k$$. We have 4 variables and 3 equations.
Therefore, D is most likely to be the answer.

Condition 1) is sufficient since $$16 = y = 4k$$, and so $$k = 4$$. Then $$x = 3k = 12.$$
Condition 2) is also sufficient since $$4 = z – y = 5k – 4k = k$$. So, $$x = 3k = 12.$$

Tip 1) of VA method states that D is most likely to be the answer if conditions 1) and 2) give similar information.

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Re: The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value  [#permalink]

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13 Sep 2018, 09:21
1
Dear moderator,

This is not a work rate problem. Please amend the tag.
Thanks
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Posts: 50579
Re: The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value  [#permalink]

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13 Sep 2018, 20:09
Shank18 wrote:
Dear moderator,

This is not a work rate problem. Please amend the tag.
Thanks

______________
Done. Thank you.
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Re: The numbers x, y and z are in the ratio 3 to 4 to 5. What is the value &nbs [#permalink] 13 Sep 2018, 20:09
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