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

Redeem

OG12 DS 120. How to find x percent more?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 83
Joined: Tue Mar 31, 2009 11:03 am
Thanked: 3 times

OG12 DS 120. How to find x percent more?

by EricKryk » Wed Jun 23, 2010 1:12 pm
The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998. Was the annual rent collected by the corporation from the building more in 1999 than in 1997?

(1) x>y

(2) xy/100 < (x-y)
Top
Source: — Data Sufficiency |
User avatar
GMAT Instructor
Posts: 1052
Joined: Fri May 21, 2010 1:30 am
Thanked: 335 times
Followed by:98 members

by Patrick_GMATFix » Wed Jun 23, 2010 1:18 pm
The correct answer is B. Detailed solutions and a couple of good take-away lessons are available here.

-Patrick
  • Ask me about tutoring.
Top
Senior | Next Rank: 100 Posts
Posts: 83
Joined: Tue Mar 31, 2009 11:03 am
Thanked: 3 times

by EricKryk » Thu Jun 24, 2010 8:08 am
Thanks Patrick. Very helpful explanation!!
Top
User avatar
Legendary Member
Posts: 1460
Joined: Tue Dec 29, 2009 1:28 am
Thanked: 135 times
Followed by:7 members

by selango » Thu Jun 24, 2010 8:52 am
Let annual rent for 1997 -100

1998 - 100+x

1999- (100+x)-y/100(100+x)

Rephrasing the question,


(100+x)-y/100(100+x)>100

(10000+100x-100y-xy)/100>100

10000+100(x-y)-xy>10000

100(x-y)-xy>0

-->xy/100<x-y

Option B satisfies this

Hence B
Top
Senior | Next Rank: 100 Posts
Posts: 33
Joined: Thu Apr 16, 2009 6:58 am
Location: Boston
Thanked: 2 times

by bynddrvn » Fri Aug 13, 2010 1:05 pm
Thank you very much for the detailed solution.

I solved for the 1st statement by just taking a high level approach. If we start with a number, let's say 100 in 1997, then increase this amount by some percentage, the percent decrease in 1998 would HAVE to be a smaller percentage just to equal what we started with in 1997; because we are multiplying the percent decrease against a larger number. Simply knowing that we have a smaller percentage doesn't help because it may or may not decrease the total back down to our original number.

Not sure if this helps, my mind works a bit differently.
Top
Post new topic Post Reply
• Page 1 of 1