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: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
24 Oct 2012, 05:17
2
1
LM wrote:
If x, y, and z are positive integers, x is a factor of 2y, and 3y is a factor of z, which of the following must also be an integer?
A) \(\frac{y}{x}\)
B) \(\frac{2y}{6}\)
C) \(\frac{xy}{3z}\)
D) \(\frac{zx}{3y}\)
E) \(\frac{zy}{3x}\)
\(x\) is a factor of \(2y\), means that \(\frac{2y}{x}=integer\).
Similarly, \(3y\) is a factor of \(z\), means that \(\frac{z}{3y}=integer\). Multiply both sides of this equation by integer \(x\): \(\frac{z}{3y}*x=integer*x\) --> \(\frac{zx}{3y}=x*integer=integer*integer=integer\).
Re: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
31 Oct 2012, 06:12
1
Bunuel wrote:
LM wrote:
If x, y, and z are positive integers, x is a factor of 2y, and 3y is a factor of z, which of the following must also be an integer?
A) \(\frac{y}{x}\)
B) \(\frac{2y}{6}\)
C) \(\frac{xy}{3z}\)
D) \(\frac{zx}{3y}\)
E) \(\frac{zy}{3x}\)
\(x\) is a factor of \(2y\), means that \(\frac{2y}{x}=integer\).
Similarly, \(3y\) is a factor of \(z\), means that \(\frac{z}{3y}=integer\). Multiply both sides of this equation by integer \(x\): \(\frac{z}{3y}*x=integer*x\) --> \(\frac{zx}{3y}=x*integer=integer*integer=integer\).
Answer: D.
Hope it's clear.
Hello Bunuel,
Can we simplify the options and then attempt the Questions
For Option 5, ZY/3X can be simplified as 3Y*Y/3X --> Y*Y/X which may or may not be true. For example looking at option 4, ZX/3Y, if simplify it as ---> Z=3y and then the eqn becomes 3y*y/ 3y which gives x only
Please confirm
_________________
“If you can't fly then run, if you can't run then walk, if you can't walk then crawl, but whatever you do you have to keep moving forward.”
Re: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
01 Nov 2012, 07:13
mridulparashar1 wrote:
Bunuel wrote:
LM wrote:
If x, y, and z are positive integers, x is a factor of 2y, and 3y is a factor of z, which of the following must also be an integer?
A) \(\frac{y}{x}\)
B) \(\frac{2y}{6}\)
C) \(\frac{xy}{3z}\)
D) \(\frac{zx}{3y}\)
E) \(\frac{zy}{3x}\)
\(x\) is a factor of \(2y\), means that \(\frac{2y}{x}=integer\).
Similarly, \(3y\) is a factor of \(z\), means that \(\frac{z}{3y}=integer\). Multiply both sides of this equation by integer \(x\): \(\frac{z}{3y}*x=integer*x\) --> \(\frac{zx}{3y}=x*integer=integer*integer=integer\).
Answer: D.
Hope it's clear.
Hello Bunuel,
Can we simplify the options and then attempt the Questions
For Option 5, ZY/3X can be simplified as 3Y*Y/3X --> Y*Y/X which may or may not be true. For example looking at option 4, ZX/3Y, if simplify it as ---> Z=3y and then the eqn becomes 3y*y/ 3y which gives x only
Please confirm
We are not given that z=3y, we are given that z=3y*integer (3y is a factor of z). Now, if we substitute z in \(\frac{zx}{3y}\), we'l get: \(\frac{zx}{3y}=\frac{(3y*integer)*x}{3y}=integer*x=integer\).
Re: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
17 Jun 2017, 21:15
I have a doubt here. Option E is also possible. The answer option is zy/3x z is divisible by 3y. that means z/3 will always yield an integer. y/x will also give an integer. When we multiply these 2 the result should be an integer as all x,y,z are integers. Please clarify if I am missing something.
Re: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
18 Jun 2017, 03:07
laasshetty wrote:
I have a doubt here. Option E is also possible. The answer option is zy/3x z is divisible by 3y. that means z/3 will always yield an integer. y/x will also give an integer. When we multiply these 2 the result should be an integer as all x,y,z are integers. Please clarify if I am missing something.
You are not reading the question carefully.
The question asks: which of the following MUST also be an integer? Not COULD also be an integer?
_________________
Re: If x, y, and z are positive integers, x is a factor of 2y
[#permalink]
Show Tags
30 Jan 2018, 14:57
Hi All,
I'm a big fan of TESTing VALUES (which is showcased in several of the explanations) - it's perfect for these types of questions. In addition, the answer choices are written in such a way that you can answer this question using Number Property rules....
In the prompt, we're told that "3Y is a factor of Z." This is just a wordy way of saying Z/3Y is an INTEGER. We're also told that X, Y and Z are positive integers.
Looking at the answers, what do you notice about answer D?
ZX/3Y....
It's interesting that the letters in in the numerator are NOT in alphabetical order. I wonder why THAT is? Is it to hide the fact that this answer has Z/3Y in it? We already know that Z/3Y is an integer and we know that X is an integer too.
Answer D literally translates into (integer)(integer)....which is ALWAYS an integer.
close
66% (01:38) correct 
