Last visit was: 24 Jul 2024, 11:01 It is currently 24 Jul 2024, 11:01
Close
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
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.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Tags:
Difficulty: 505-555 Level,   Algebra,                  
Show Tags
Hide Tags
avatar
Intern
Intern
Joined: 06 Feb 2009
Posts: 3
Own Kudos [?]: 25 [25]
Given Kudos: 0
Concentration: Finance
Schools:HBS
Send PM
Most Helpful Reply
Math Expert
Joined: 02 Sep 2009
Posts: 94607
Own Kudos [?]: 643591 [6]
Given Kudos: 86737
Send PM
General Discussion
Senior Manager
Senior Manager
Joined: 04 Jan 2014
Posts: 253
Own Kudos [?]: 147 [2]
Given Kudos: 15
GMAT 1: 660 Q48 V32
GMAT 2: 630 Q48 V28
GMAT 3: 680 Q48 V35
Send PM
User avatar
Director
Director
Joined: 25 Apr 2012
Posts: 529
Own Kudos [?]: 2322 [1]
Given Kudos: 740
Location: India
GPA: 3.21
WE:Business Development (Other)
Send PM
Re: What is the value of x/(yz) ? [#permalink]
1
Kudos
What is the value of x/(yz) ?

(1) x = y/2 and z = 2x/5
(2) x/z = 5/2 and 1/y = 1/10

Sol: St 1---> x=2y and z=2x/5 or 4y/5
Thus we have 2y/(y*4y/5) or 10y/4y^2---> 10/4y but we don't the value of y so not sufficient

St 2: x=5/2z and y=10
Subsituting we get (5z/2)/10*z or 5z/20z or 1/4
Ans B
Manager
Manager
Joined: 20 Dec 2013
Posts: 183
Own Kudos [?]: 291 [1]
Given Kudos: 35
Location: India
Send PM
Re: What is the value of x/(yz) ? [#permalink]
1
Kudos
Option B:
From S1: replacing y=2x and z=2x/5 does not give a value for x/(yz)
Not sufficient

From S2: x/z * 1/y are both given
So value=1/4
Sufficient
avatar
Intern
Intern
Joined: 12 Aug 2014
Posts: 11
Own Kudos [?]: 1 [0]
Given Kudos: 72
Send PM
Re: What is the value of x/(yz) ? [#permalink]
Bunuel wrote:
SOLUTION

What is the value of x/(yz) ?

(1) \(x = \frac{y}{2}\) and \(z = \frac{2x}{5}\). If \(y=10\), then \(x=5\), \(z=2\) and in this case \(\frac{x}{yz}=\frac{5}{20}=\frac{1}{4}\) BUT if \(y=20\), then \(x=10\), \(z=4\) and in this case \(\frac{x}{yz}=\frac{10}{80}=\frac{1}{8}\). Not sufficient.

(2) \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\). Multiply these two equations: \(\frac{x}{yz}=\frac{5}{20}\). Sufficient.

Answer: B.



In statement 1.......I tried to solve it through algebra. y= 2x and z=2x/5 so if we pick up expression given in question and replace y and z with 2x and 2x/5 respectively......the entire expression would only have one variable(x).....by a little calculation all x in expressions would be cancelled with each others and we will get 4/5 as answer of expression. Than why sttment 1 is insufficient? can you please guide me? :cry:
Math Expert
Joined: 02 Sep 2009
Posts: 94607
Own Kudos [?]: 643591 [0]
Given Kudos: 86737
Send PM
Re: What is the value of x/(yz) ? [#permalink]
Expert Reply
mulhinmjavid wrote:
Bunuel wrote:
SOLUTION

What is the value of x/(yz) ?

(1) \(x = \frac{y}{2}\) and \(z = \frac{2x}{5}\). If \(y=10\), then \(x=5\), \(z=2\) and in this case \(\frac{x}{yz}=\frac{5}{20}=\frac{1}{4}\) BUT if \(y=20\), then \(x=10\), \(z=4\) and in this case \(\frac{x}{yz}=\frac{10}{80}=\frac{1}{8}\). Not sufficient.

(2) \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\). Multiply these two equations: \(\frac{x}{yz}=\frac{5}{20}\). Sufficient.

Answer: B.



In statement 1.......I tried to solve it through algebra. y= 2x and z=2x/5 so if we pick up expression given in question and replace y and z with 2x and 2x/5 respectively......the entire expression would only have one variable(x).....by a little calculation all x in expressions would be cancelled with each others and we will get 4/5 as answer of expression. Than why sttment 1 is insufficient? can you please guide me? :cry:


When you substitute y = 2x and z = 2x/5 into x/(yz) you get 5/(4x). Without knowing the value of x we cannot get the value of 5/(4x).

Hope it's clear.
examPAL Representative
Joined: 07 Dec 2017
Posts: 1048
Own Kudos [?]: 1799 [0]
Given Kudos: 26
Send PM
Re: What is the value of x/(yz) ? [#permalink]
carcass wrote:
What is the value of \(\frac{x}{yz}\)?

(1) \(x = \frac{y}{2}\) and \(z = \frac{2x}{5}\)

(2) \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\)


We'll try to simplify and rearrange our data to create x/yz.
This is a Precise approach.

(1) we have x = y/2 --> x/y = 1/2. Multiplying by z = 2x/5 gives xz/y = (2x^2)/(5y), which can have many different values.
Insufficient.

(2) multiplying x/z = 5/2 by 1/y = 1/10 gives x/yz = 5/20, a unique value.
Sufficient.

(B) is our answer.
GMAT Club Legend
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 6804
Own Kudos [?]: 30861 [0]
Given Kudos: 799
Location: Canada
Send PM
Re: What is the value of x/(yz) ? [#permalink]
Expert Reply
Top Contributor
financeguy25 wrote:
What is the value of \(\frac{x}{yz}\)?


(1) \(x = \frac{y}{2}\) and \(z = \frac{2x}{5}\)

(2) \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\)

DS86602.01


Target question: What is the value of x/yz?

Statement 1: x = y/2 and z = 2x/5
Take x = y/2 and multiply both sides by 2 to get: 2x = y
Also given: z = 2x/5

This allows us to take our target expression, x/yz, and replace y and z to get: x/yz = x/[(2x)(2x/5)]
= x/(4x²/5)
= (x)(5/4x²)
= 5x/4x²
= 5/4x
Since x can be any value, we can see that we cannot answer the target question with certainty
Statement 1 is NOT SUFFICIENT

Statement 2: x/z = 5/2 and 1/y = 1/10[
Important: we are trying to find the value of x/yz
Notice that we can take x/yz and rewrite it as (x/z)(1/y), which works nicely with our given information.
We get: x/yz = (x/z)(1/y) = (5/2)(1/10) = 5/20 = 1/4
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent
UNC Kenan Flagler Moderator
Joined: 18 Jul 2015
Posts: 237
Own Kudos [?]: 252 [0]
Given Kudos: 120
GMAT 1: 530 Q43 V20
WE:Analyst (Consumer Products)
Send PM
Re: What is the value of x/(yz) ? [#permalink]
financeguy25 wrote:
What is the value of \(\frac{x}{yz}\)?


(1) \(x = \frac{y}{2}\) and \(z = \frac{2x}{5}\)

(2) \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\)

DS86602.01


Statement - I (Insufficient)
1. \(x = \frac{y}{2}\) can be written as \(\frac{x}{y} = \frac{1}{2}\)

2. Substituting \(\frac{x}{y} = \frac{1}{2}\) and \(z = \frac{2x}{5}\) in \(\frac{x}{yz}\) we get \(\frac{1}{2} * \frac{5}{2x}\)

3. As we see, one variable is remains uncancelled and hence we cannot arrive at the final answer

Statement - II (Sufficient)
Substituting \(\frac{x}{z} = \frac{5}{2}\) and \(\frac{1}{y} = \frac{1}{10}\) in \(\frac{x}{yz}\) we get \(\frac{5}{2}*\frac{1}{10} = \frac{1}{4}\)

Ans. B
Intern
Intern
Joined: 05 Feb 2021
Posts: 6
Own Kudos [?]: 2 [1]
Given Kudos: 70
GMAT 1: 710 Q50 V35
GMAT 2: 750 Q50 V42
Send PM
Re: What is the value of x/(yz) ? [#permalink]
1
Kudos
did anyone thought it was y^z instead of y*z at first?
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 34067
Own Kudos [?]: 853 [0]
Given Kudos: 0
Send PM
Re: What is the value of x/(yz) ? [#permalink]
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.
GMAT Club Bot
Re: What is the value of x/(yz) ? [#permalink]
Moderator:
Math Expert
94606 posts