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

 It is currently 13 Oct 2019, 21:03

### 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

# The positive quantities x,y and z vary over time, and 2x/3 always equa

Author Message
TAGS:

### Hide Tags

VP
Joined: 31 Oct 2013
Posts: 1475
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
The positive quantities x,y and z vary over time, and 2x/3 always equa  [#permalink]

### Show Tags

08 Feb 2019, 15:07
1
00:00

Difficulty:

25% (medium)

Question Stats:

76% (01:38) correct 24% (01:53) wrong based on 38 sessions

### HideShow timer Statistics

The positive quantities x,y and z vary over time, and $$\frac{2x}{3}$$ always equals 16yz. If y is tripled and z is halved, then x is

A) decreased by 50%
B)decreased by 33.33%
C)Unchanged
D)Increased by 33.33%
E)increased by 50%
NUS School Moderator
Joined: 18 Jul 2018
Posts: 1028
Location: India
Concentration: Finance, Marketing
WE: Engineering (Energy and Utilities)
Re: The positive quantities x,y and z vary over time, and 2x/3 always equa  [#permalink]

### Show Tags

08 Feb 2019, 21:01
1
2x/3 = 16yz
x = 24yz

New y = 3y and z = 1/2z
New x = 36yz

(36yz-24yz)/24yz = 12/24*100 = 50% Increase

_________________
Press +1 Kudos If my post helps!
Director
Joined: 09 Mar 2018
Posts: 997
Location: India
Re: The positive quantities x,y and z vary over time, and 2x/3 always equa  [#permalink]

### Show Tags

08 Feb 2019, 21:22
selim wrote:
The positive quantities x,y and z vary over time, and $$\frac{2x}{3}$$ always equals 16yz. If y is tripled and z is halved, then x is

A) decreased by 50%
B)decreased by 33.33%
C)Unchanged
D)Increased by 33.33%
E)increased by 50%

2x/3 = 16yz

Initially x = 24yz

After y is tripled and z is halved

x became = 36yz

% Increase = {(36-24)*yz/ 24yz } * 100
= 50 %

E
_________________
If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.
Senior Manager
Joined: 12 Sep 2017
Posts: 301
The positive quantities x,y and z vary over time, and 2x/3 always equa  [#permalink]

### Show Tags

13 Feb 2019, 16:05
Afc0892 wrote:
2x/3 = 16yz
x = 24yz

New y = 3y and z = 1/2z
New x = 36yz

(36yz-24yz)/24yz = 12/24*100 = 50% Increase

Hello Afc0892 !

What's wrong with my approach?

$$2/3$$ = 66%

$$(2x)/3 = 16yz$$

$$(2x)/3 = 16(3y)(z/2)$$

$$((2x)/3 = 16(3y)(z/2))*(2/3)$$

$$((4x)/6 = 16(y)(z))$$

$$2/3$$ = 66%
$$4/9$$ = 44% --- Decrease
The positive quantities x,y and z vary over time, and 2x/3 always equa   [#permalink] 13 Feb 2019, 16:05
Display posts from previous: Sort by