BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

If m > 0, y > 0, and x is m percent of 2y, then, in te

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Thu Sep 20, 2018 6:00 pm
BTGmoderatorDC wrote:If m > 0, y > 0, and x is m percent of 2y, then, in terms of y, m is what percent of x?

A. y/200
B. 2y
C. 50y
D. 50/y
E. 5000/y
Let y=100, implying that 2y = 200.
Let m=100.

x is m percent of 2y.
Since m=100 and 2y=200, x = 100% of 200 = 200.

m is what percent of x?
m/x = 100/200 = 1/2 = 50%. This is our target.

Now plug y=100 into the answers to see which yields the target value of 50.
Only E works:
5000/y = 5000/100 = 50.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
User avatar
GMAT Instructor
Posts: 1449
Joined: Sat Oct 09, 2010 2:16 pm
Thanked: 59 times
Followed by:33 members

If m > 0, y > 0, and x is m percent of 2y, then, in te

by fskilnik@GMATH » Thu Sep 20, 2018 6:52 pm
BTGmoderatorDC wrote:If m > 0, y > 0, and x is m percent of 2y, then, in terms of y, m is what percent of x?

A. y/200
B. 2y
C. 50y
D. 50/y
E. 5000/y
Source: Manhattan Prep
Obs.: (to our students) This is one of those problems in which we must interpret 1/2= 50% as 50 ("percent omitted") because the term "percent" is in the FOCUS.
(Don´t forget "the hidden butterfly mistake"!)

\[x = \frac{m}{{100}}\left( {2y} \right)\,\,\,\,\,\,\,\,\,\,\left[ {m,y\,\, > 0} \right]\]
\[?\,\,\,:\,\,\,\frac{m}{x} \cdot 100\left( \% \right) = f\left( y \right)\]
\[x = \frac{m}{{100}}\left( {2y} \right)\,\,\,\,\,\mathop \Rightarrow \limits^{{\text{FOCUS}}!} \,\,\,\,\,\frac{m}{x} = \frac{{50}}{y}\,\,\,\,\,\mathop \Rightarrow \limits^{{\text{FOCUS}}!} \,\,\,\,\,?\,\, = \,\,\frac{m}{x} \cdot 100\left( \% \right) = \frac{{50}}{y} \cdot 100\left( \% \right)\,\,\,\,\, \Rightarrow \,\,\,\,\left( E \right)\]

This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
English-speakers :: https://www.gmath.net
Portuguese-speakers :: https://www.gmath.com.br
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2095
Joined: Tue Dec 04, 2012 3:22 pm
Thanked: 1443 times
Followed by:247 members

by ceilidh.erickson » Fri Sep 21, 2018 1:20 pm
BTGmoderatorDC wrote:If m > 0, y > 0, and x is m percent of 2y, then, in terms of y, m is what percent of x?

A. y/200
B. 2y
C. 50y
D. 50/y
E. 5000/y

OA E

Source: Manhattan Prep
Here's another way to set it up algebraically:

x is m percent of 2y --->
\[x = \frac{m}{{100}}\left( {2y} \right)\]

m is what percent of x? Create a new variable "n" for the "what" --->
\[m = \frac{n}{{100}}\left( {x} \right)\]

Now combine the two equations by substituting in for x:
\[m = \frac{n}{{100}}\ \cdot \frac{m}{{100}}\left( {2y} \right)\]

Divide both sides by m:
\[1 = \frac{n}{{100}}\ \cdot \frac{1}{{100}}\left( {2y} \right)\]

Isolate n:
\[\frac{1}{{2y}}\ = \frac{n}{{100}}\ \cdot \frac{1}{{100}}\]
\[\frac{1}{{2y}}\ = \frac{n}{{10,000}}\]
\[\frac{10,000}{{2y}}\ = n\]
\[\frac{5,000}{{y}}\ = n\]

The answer is E.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2095
Joined: Tue Dec 04, 2012 3:22 pm
Thanked: 1443 times
Followed by:247 members

by ceilidh.erickson » Fri Sep 21, 2018 1:31 pm
Here's another similar problem to try, both algebraically and with plugging numbers:
https://www.beatthegmat.com/if-m-0-and- ... tml#800983
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Thu Sep 27, 2018 4:26 pm
BTGmoderatorDC wrote:If m > 0, y > 0, and x is m percent of 2y, then, in terms of y, m is what percent of x?

A. y/200
B. 2y
C. 50y
D. 50/y
E. 5000/y
We are given that x is m percent of 2y. Thus:

x = (m/100)(2y)

We need to determine m as a percentage of x, i.e., (m/x)(100).

Let's simplify our equation:

x = (m/100)(2y)

x/m = 2y/100

x/m = y/50

m/x = 50/y

(m/x)(100) = (50/y)(100)

(m/x)(100) = 5000/y

Answer: E

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Post new topic Post Reply
• Page 1 of 1