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

 It is currently 18 Oct 2018, 22:25

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

If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y|

Author Message
TAGS:

Hide Tags

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 6386
GMAT 1: 760 Q51 V42
GPA: 3.82
If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y|  [#permalink]

Show Tags

Updated on: 22 Nov 2017, 19:43
00:00

Difficulty:

75% (hard)

Question Stats:

55% (02:32) correct 45% (02:12) wrong based on 61 sessions

HideShow timer Statistics

[GMAT math practice question]

If $$2x+y≠0$$, is $$\frac{x}{2x+y}<1$$ ?

1) $$|x|=10|y|$$
2) $$y>0$$

_________________

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" "Free Resources-30 day online access & Diagnostic Test" "Unlimited Access to over 120 free video lessons - try it yourself" Originally posted by MathRevolution on 21 Nov 2017, 18:21. Last edited by MathRevolution on 22 Nov 2017, 19:43, edited 1 time in total. Senior Manager Joined: 31 Jul 2017 Posts: 477 Location: Malaysia Schools: INSEAD Jan '19 GMAT 1: 700 Q50 V33 GPA: 3.95 WE: Consulting (Energy and Utilities) Re: If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y| [#permalink] Show Tags 21 Nov 2017, 22:41 MathRevolution wrote: [GMAT math practice question] If $$2x+y≠0$$, is $$\frac{x}{2x}+y<1$$ ? 1) $$|x|=10|y|$$ 2) $$y>0$$ Hi MathRevolution Not Sure if the $$OA$$ is correct as per the question. We need to find if $$y<1/2$$? From Stmnt 1: X = 10, y = -1 and X = -10, y =1 So, Not Sufficient. _________________ If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !! Math Revolution GMAT Instructor Joined: 16 Aug 2015 Posts: 6386 GMAT 1: 760 Q51 V42 GPA: 3.82 Re: If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y| [#permalink] Show Tags 22 Nov 2017, 19:49 2 => Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is 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. Since we have 2 variables (x and y) and 0 equations, C is most likely to be the answer. Conditions 1) & 2) $$|x|=10|y| ⇔ x = ±10y$$ Case 1: If $$x=10y$$, then $$\frac{x}{2x+y}= \frac{10y}{20y+y}= \frac{10y}{21y}=\frac{10}{21}<1$$, and the answer is ‘yes’. Case 2:If $$x= -10y$$, then $$\frac{x}{2x+y} = \frac{-10y}{-20y+y} = \frac{-10y}{-19y} =\frac{10}{19}<1$$, and the answer is ‘yes’. Both conditions, applied together, are sufficient. Since this is an inequality question (one of the key question areas), CMT (Common Mistake Type) 4 (A) tells us that we need to also consider conditions 1) and 2) separately. Condition 1) $$|x|=10|y| ⇔ x = ±10y$$ Case 1: If $$x = 10y$$, then $$\frac{x}{2x+y}= \frac{10y}{20y+y}= \frac{10y}{21y}=\frac{10}{21}<1$$, and the answer is ‘yes’. Case 2: If $$x = -10y$$, then $$\frac{x}{2x+y}= \frac{-10y}{-20y+y}= \frac{-10y}{-19y}=\frac{10}{19}<1$$ and the answer is ‘yes’. Since the answer is ‘yes’ in both cases, this condition is sufficient. Condition 2) If $$x = -2$$ and $$y = 1$$, then $$\frac{x}{2x+y} = \frac{-2}{-4+1} = \frac{-2}{-3} = \frac{2}{3} <1$$, and the answer is ‘yes’. If $$x=-2$$ and $$y=3$$, then $$\frac{x}{2x+y} = \frac{-2}{-4+3} = \frac{-2}{-1} =2>1$$, and the answer is ‘no’. This is NOT sufficient. Note: Since this condition is so trivial, it is unlikely to be sufficient by Tip 4) of the VA method. The answer is A. Normally, in problems which require 2 or more additional equations, such as those in which the original conditions include 2 variables, or 3 variables and 1 equation, or 4 variables and 2 equations, each of conditions 1) and 2) provide an additional equation. In these problems, the two key possibilities are that C is the answer (with probability 70%), and E is the answer (with probability 25%). Thus, there is only a 5% chance that A, B or D is the answer. This occurs in common mistake types 3 and 4. Since C (both conditions together are sufficient) is the most likely answer, we save time by first checking whether conditions 1) and 2) are sufficient, when taken together. Obviously, there may be cases in which the answer is A, B, D or E, but if conditions 1) and 2) are NOT sufficient when taken together, the answer must be E). Answer: A _________________ 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"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Senior Manager
Joined: 02 Apr 2014
Posts: 471
GMAT 1: 700 Q50 V34
Re: If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y|  [#permalink]

Show Tags

09 Dec 2017, 12:14
$$x / (2x + y) < 1$$ ?

rearranging , $$1 / ( 2 + y/x) < 1$$ ?

Statement 1: $$|x| = 10|y|$$
=> $$|y|/|x| = 1/10$$
so max value of y/x is 1/10 => $$1 / (2+ (1/10))$$=> 1/2.1 is less than 1
and min value of y/x is - 1/10 => $$1 / (2 - (1/10))$$=> 1/1.9 is also less than 1

Sufficient

Statement 2: y> 0, no idea about x => Insufficient

Re: If 2x+y≠0, is x/2x+y<1 ? 1) |x|=10|y| &nbs [#permalink] 09 Dec 2017, 12:14
Display posts from previous: Sort by