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

Redeem

GMAT PREP - percentage change

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 131
Joined: Fri Jun 18, 2010 10:19 am
Location: New York, NY
Thanked: 10 times

GMAT PREP - percentage change

by aleph777 » Sun Feb 27, 2011 5:49 am
Ok, my last prep review for the day...

I'm including two problems here, both of which I got correct, but I was a little shaky on my theory.

Basically, I approached them thinking that, in order to determine the change, you need either the new and the old or the percent change from new to old. You don't actually need the values, though. Is this the appropriate concept to apply here?

Thank you!
Attachments
Screen shot 2011-02-27 at 7.58.29 AM.png
Screen shot 2011-02-27 at 8.01.59 AM.png
Top
Source: — Data Sufficiency |
Legendary Member
Posts: 1578
Joined: Sun Dec 28, 2008 1:49 am
Thanked: 82 times
Followed by:9 members
GMAT Score:720

by maihuna » Sun Feb 27, 2011 6:22 am
For Q1, assuming 100 is the pop in 70's, you know pop in 80's is 120 and that in 90's 1.30*120 = 156

so %tage increase over the period is 56.
Charged up again to beat the beast :)
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Sun Feb 27, 2011 6:23 am
First One:

Statement 1: We have the population in 1970, but no relation of that with that of in 1980 or 1990.

Not sufficient

Statement 2: We have the relation of population in 1980 and 1990 with that in 1970 in terms of percentage. Hence, we can represent the population of 1980 and 1990 as some fraction of the population of 1970. And hence we can find the percentage change between them too.

Sufficient

The correct answer is B.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Sun Feb 27, 2011 6:26 am
Second One: Refer to this post : https://www.beatthegmat.com/marla-t72684.html#329150
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
User avatar
Legendary Member
Posts: 516
Joined: Mon Nov 02, 2009 6:42 am
Location: Mumbai
Thanked: 14 times
Followed by:1 members
GMAT Score:710

by ankurmit » Tue Mar 01, 2011 8:38 pm
Anurag@Gurome wrote:First One:

Statement 1: We have the population in 1970, but no relation of that with that of in 1980 or 1990.

Not sufficient

Statement 2: We have the relation of population in 1980 and 1990 with that in 1970 in terms of percentage. Hence, we can represent the population of 1980 and 1990 as some fraction of the population of 1970. And hence we can find the percentage change between them too.

Sufficient

The correct answer is B.
Anurag, can you help me to find out exect percentage change from 1980 to 1990.

I am bit confused.
--------
Ankur mittal
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 436
Joined: Tue Feb 08, 2011 3:07 am
Thanked: 72 times
Followed by:6 members

by manpsingh87 » Tue Mar 01, 2011 9:28 pm
The first question talks about the percent increase,

statement 1) gives data about the 1970 population, which is not sufficient to evaluate the percent increase because we don't know the population in the year 1980 and 1990.

statement 2) suppose population in 1970 is 100, so in 1980 it becomes 120, and in 1990 it becomes 130, so the percentage increase from 1980 to 1930 would be; {(130-120)/120}*100
= 100/12 = 8.33%;

Hence statement 2 alone is sufficient to answer the question..!!
O Excellence... my search for you is on... you can be far.. but not beyond my reach!
Top
Post new topic Post Reply
• Page 1 of 1