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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: What is the distance between x and y on the number line? [#permalink]
25 Mar 2012, 23:22

1

This post received KUDOS

Expert's post

What is the distance between x and y on the number line?

Question: |x-y|=?

(1) |x| – |y| = 5. Not sufficient: consider x=10, y=5 and x=10, y=-5. (2) |x| + |y| = 11. Not sufficient: consider x=10, y=1 and x=10, y=-1.

(1)+(2) Solve the system of equation for |x| and |y|: sum two equations to get 2|x|=16 --> |x|=8 --> |y|=3. Still not sufficient to get the single numerical value of |x-y|, for example consider: x=8, y=3 and x=8, y=-3. Not sufficient.

Re: What is the distance between x and y on the number line? [#permalink]
26 Mar 2012, 00:30

Solving the two equations will give x as 8 and y as 3. But since mod sign is there, x and y can take any value, either positive or negative. Hence, both the statements are insufficient.

Re: What is the distance between x and y on the number line? [#permalink]
23 Dec 2012, 06:55

Expert's post

PraPon wrote:

Bunuel can you clarify what can be wrong below approach?

Answer choice can be (C) ------------------------------------- By multiplying statements 1 & 2 (1) |x| – |y| = 5 (2) |x| + |y| = 11

X^2-Y^2=55

i.e. (x+y)(x-y)=55 = 11 * 5 = - 11 * - 5 (i.e. both factors are either positive or negative)

Hence only two possible solutions for this – i.e. either (x=8 & y=3) OR (x= -8 & y= -3) In both cases the distance between them is 5.

-> Hence Answer is C.

(x+y)(x-y)=55 does not mean that either (x=8 & y=3) OR (x= -8 & y= -3). There are more integer solutions (for example x=+/-28 and y=+/-27) and infinitely many non-integer solutions.
_________________

Re: What is the distance between x and y on the number line? [#permalink]
18 Jul 2013, 11:56

What is the distance between x and y on the number line?

(1) |x| – |y| = 5

|11|-|6|=5 Distance is five

|11|-|-6|=5 Distance is seventeen INSUFFICIENT

(2) |x| + |y| = 11

|5|+|6| = 11 Distance is one

|5|+|-6| = 11 Distance is negative eleven

INSUFFICIENT

This problem, to me, seems much easier than a 700 level question. a and b provide us with multiple valid values for x and y, none of which entirely (i.e. are the same) Can someone tell me if I am oversimplifying this problem? Thanks!

gmatclubot

Re: What is the distance between x and y on the number line?
[#permalink]
18 Jul 2013, 11:56