NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 03:39 It is currently 25 Apr 2024, 03:39
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

m20 #13

User avatar
gmattokyo
Manager
Manager
Joined: 18 Aug 2009
Posts: 214
Own Kudos [?]: 1622 [0]
Given Kudos: 9
Send PM
m20 #13 [#permalink] New post   19 Nov 2009, 06:46
The price of a house decreased by \(x\%\) from 1998 to 1999 and increased by \(y\%\) from 1999 to 2000. If the house cost \(M\) dollars in 2000, how much did it cost in 1998?

A. \(100 * \frac{\frac{M}{1 + x}}{1 - y}\)

B. \(\frac{\frac{M}{1 + \frac{x}{100}}}{1 - \frac{y}{100}}\)

C. \(\frac{M}{1 + \frac{x}{100} - \frac{y}{100}}\)

D. \(\frac{\frac{10,000M}{100 + y}}{100 - x}\)

E. \(\frac{\frac{10,000M}{100 + x}}{100 - y}\)

Show Spoiler
Denote \(P\) as the price of the house in 1998. We know that \(M = P(1 - \frac{x}{100})(1 + \frac{y}{100})\) . From this equation \(P = \frac{\frac{M}{1 - \frac{x}{100}}}{1 + \frac{y}{100}}\) or \(\frac{\frac{10,000M}{100 + y}}{100 - x}\) .

Is there something wrong in the solution or I'm misreading it?
Say \(X={1 - \frac{x}{100}}\) and \(Y={1 - \frac{y}{100}}\)
If I rewrite the middle step \(M=P(X)(Y)\) => \(P=\frac{M}{XY}\)
=> some representation of \(\frac{10,000M}{(100 + y)(100 - x)}\)


Archived Topic
Hi there,
Archived GMAT Club Tests question - no more replies possible.
Where to now? Try our up-to-date Free Adaptive GMAT Club Tests for the latest questions.
Still interested? Check out the "Best Topics" block below for better discussion and related questions.
Thank you for understanding, and happy exploring!
User avatar
gmattokyo
Manager
Manager
Joined: 18 Aug 2009
Posts: 214
Own Kudos [?]: 1622 [0]
Given Kudos: 9
Send PM
Re: m20 #13 [#permalink] New post   19 Nov 2009, 06:52
oops... after posting, I realized both of the solution mentioned above are the same :oops:
Sorry abt that
User avatar
AN225
Manager
Manager
Joined: 29 Sep 2010
Status:Happy to join ROSS!
Posts: 234
Own Kudos [?]: 282 [0]
Given Kudos: 48
Concentration: General Management, Strategy
Schools: Ross '14 (M$)
Send PM
Reviews Badge
Re: m20 #13 [#permalink] New post   14 Jan 2011, 13:28
gmattokyo, I had the same question as you did, but after your comment I realized the solution as well :)
User avatar
CMcAboy
Manager
Manager
Joined: 01 Mar 2009
Posts: 177
Own Kudos [?]: 94 [0]
Given Kudos: 23
Location: United States
Concentration: Strategy, Technology
Schools: Goizueta '16 (M$) Duke '16 (D) Tuck '16 (D) Johnson '16 (D) Darden '16 (D) Ross '16 (WL) McDonough '16 (A)
GMAT 1: 660 Q47 V34
GMAT 2: 680 Q46 V38
GPA: 3.2
WE:Consulting (Computer Software)
Send PM
Re: m20 #13 [#permalink] New post   03 Jul 2012, 06:34
Did anyone try to use the VIC (Variable In Choice) method? I got the same result for A as I did for D.

I Used the following values:
Original Price of House = 100
X = 10
Y = 10

Now, we can calculate M:
M= 100*(11/10)*(9/10)

M= 99



A) 100 * [(99 / 11) / 9] = 100 * [99/99] = 100

D) [ 10,000(99) / (100+10) ] / (100 - 10) = [ 10,000(99) / 90 * 110 ] = [ 10,000(99) / (9*10) * (11*10) ] = [ 10,000(99) / (9*11) * (10*10) ] = [ 10,000(99) / (99) * (100) ] = 100
avatar
damamikus
Intern
Intern
Joined: 10 Jan 2014
Posts: 16
Own Kudos [?]: 35 [0]
Given Kudos: 6
Send PM
Re: m20 #13 [#permalink] New post   22 Feb 2014, 02:46
Bump

I'm also having trouble trying to understand the solution.

I used M=1500; x=50; y=50. this gives a 1998 selling price of 2000 (2000*0.5*1.5=1500=M). If i use these values and plug them into both B and D i get the same result. wheres my mistake? :?

cheers
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92912
Own Kudos [?]: 618898 [0]
Given Kudos: 81595
Send PM
CAT Tests Forum Quiz Mode
Re: m20 #13 [#permalink] New post   22 Feb 2014, 03:45
Expert Reply
damamikus wrote:
Bump

I'm also having trouble trying to understand the solution.

I used M=1500; x=50; y=50. this gives a 1998 selling price of 2000 (2000*0.5*1.5=1500=M). If i use these values and plug them into both B and D i get the same result. wheres my mistake? :?

cheers


Note that for plug-in method it might happen that for some particular number(s) more than one option may give "correct" answer. In this case just pick some other numbers and check again these "correct" options only.

Hope it helps.

Archived Topic
Hi there,
Archived GMAT Club Tests question - no more replies possible.
Where to now? Try our up-to-date Free Adaptive GMAT Club Tests for the latest questions.
Still interested? Check out the "Best Topics" block above for better discussion and related questions.
Thank you for understanding, and happy exploring!
GMAT Club Bot
gmatclubot
Re: m20 #13 [#permalink]
22 Feb 2014, 03:45
Moderator:
Bunuel
Math Expert
92912 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions