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

Redeem

data sufficiency

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 44
Joined: Wed Nov 03, 2010 10:07 am
Thanked: 1 times

data sufficiency

by nickhar130 » Tue Nov 09, 2010 10:55 am
During a 3-year period, the Gross Domestic Product (GDP) of Country U changed by what percvent from the first year to the second year?

1) The GDP of Country U enjoyed a constant growth rate both from the first to the second year and from the second to the third year in a certain 3-year period.

2)The GDP during the first year from 235 billion dollars. It increased to 338.4 billion dollars in the third year.


I know the answer is C, that you need both information for it to be sufficient but I'm having trouble with actually solving questions like this. When it asks questions like "changed by what percent." Can someone break it down for me to actually solving this and if have any tip or secrets for future questions similar to this and what equation to use that would be greatly appreciated.
Top
Source: — Problem Solving |
Legendary Member
Posts: 1119
Joined: Fri May 07, 2010 8:50 am
Thanked: 29 times
Followed by:3 members

by diebeatsthegmat » Tue Nov 09, 2010 6:12 pm
nickhar130 wrote:During a 3-year period, the Gross Domestic Product (GDP) of Country U changed by what percvent from the first year to the second year?

1) The GDP of Country U enjoyed a constant growth rate both from the first to the second year and from the second to the third year in a certain 3-year period.

2)The GDP during the first year from 235 billion dollars. It increased to 338.4 billion dollars in the third year.


I know the answer is C, that you need both information for it to be sufficient but I'm having trouble with actually solving questions like this. When it asks questions like "changed by what percent." Can someone break it down for me to actually solving this and if have any tip or secrets for future questions similar to this and what equation to use that would be greatly appreciated.
ehhh, i think it says if the first year, GDP=100, the second year it increase 10% so it will be 110% (=100% of the second year compared to the third year)
because the increase GDP is constant thus the third year, it will be 110 (%)
Thus, from the first to the third GDP= 110*110/100=121% =1,21
from all above, and the statement 2, does it help you to find the way to solve the problem?
Top
Master | Next Rank: 500 Posts
Posts: 437
Joined: Sat Nov 22, 2008 5:06 am
Location: India
Thanked: 50 times
Followed by:1 members
GMAT Score:580

by beat_gmat_09 » Tue Nov 09, 2010 7:48 pm
nickhar130 wrote:During a 3-year period, the Gross Domestic Product (GDP) of Country U changed by what percvent from the first year to the second year?

1) The GDP of Country U enjoyed a constant growth rate both from the first to the second year and from the second to the third year in a certain 3-year period.

2)The GDP during the first year from 235 billion dollars. It increased to 338.4 billion dollars in the third year.


I know the answer is C, that you need both information for it to be sufficient but I'm having trouble with actually solving questions like this. When it asks questions like "changed by what percent." Can someone break it down for me to actually solving this and if have any tip or secrets for future questions similar to this and what equation to use that would be greatly appreciated.
You posted in problem solving sec.
Please move this to DS.
Hope is the dream of a man awake
Top
Senior | Next Rank: 100 Posts
Posts: 44
Joined: Wed Nov 03, 2010 10:07 am
Thanked: 1 times

by nickhar130 » Tue Nov 09, 2010 7:52 pm
statement 2 says that 1st year = 235 and 3rd year = 338.4

So 2nd year = (338.4 - 235)/2 + 235 = 286.7

...but how do i answer the question "Country U changed by what percvent from the first year to the second year?"

is it 1st year(1 + x) = 2nd year
235(1 + x) = 286.7

and therefore x is 22%? im not sure.
Top
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Wed Sep 29, 2010 8:14 am
Thanked: 1 times

by vijchid » Wed Nov 10, 2010 12:18 pm
The equation basically is

235 ( 1 + x/100) (1+ x/100)=338.4

Solve for X to the percentage increase in a year.
Top
Post new topic Post Reply
• Page 1 of 1