It is currently 21 Jan 2018, 10:51

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# M01-09

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 43348

Kudos [?]: 139695 [0], given: 12794

### Show Tags

23 Nov 2017, 20:03
Spongebob02 wrote:
Bunuel wrote:
Official Solution:

The population of Linterhast was 3,600 people in 1990 and 4,800 people in 1993. If the population growth rate per thousand is constant, then what will be the population in 1996?

A. 6,000
B. 6,400
C. 7,200
D. 8,000
E. 9,600

This is a set rate problem. If the population grew by 1,200 people in the past three years, then it grew by 33 percent:
$$\frac{4800-3600}{3600} = \frac{1200}{3600} = \frac{1}{3} \approx 33%$$

Therefore in the next three years the population will grow at the same rate of 33% because the growth rate has been constant.

$$4,800 + \frac{1}{3}*4,800 = 4,800 + 1,600 = 6,400$$

Another approach is to backsolve by comparing the ratio of each answer to 4,800. For example, the ratio of 7,200 to 4,800 is not the same as the ratio of 4,800 to 3,600.

$$4,800 + \frac{1}{3}*4,800 = 4,800 + 1,600 = 6,400$$ I did not understand this equation ?

Sent from my Redmi 3S using GMAT Club Forum mobile app

In three years from 1990 to 1993 the population grew by third. Since the growth rate is constant, then in the next three years, from 1993 to 1996, the population will also grow by third.

Hope it's clear.
_________________

Kudos [?]: 139695 [0], given: 12794

Study Buddy Forum Moderator
Joined: 04 Sep 2016
Posts: 585

Kudos [?]: 140 [0], given: 321

Location: India
WE: Engineering (Other)

### Show Tags

03 Dec 2017, 15:28
Spongebob02

Quote:
$$4,800 + \frac{1}{3}*4,800 = 4,800 + 1,600 = 6,400$$ I did not understand this equation ?

We have simply converted decimal (0.33%) in to fraction (1/3) for ease of calculations while dealing with fractions.
Hope this helps!
_________________

Press kudos if you liked this post

Kudos [?]: 140 [0], given: 321

Intern
Joined: 16 Jul 2013
Posts: 34

Kudos [?]: 5 [0], given: 35

Location: Hungary
Concentration: Entrepreneurship, Marketing
GMAT 1: 720 Q48 V40
GPA: 3.37

### Show Tags

19 Dec 2017, 23:06
For me this was easier and quicker to solve using the ratios given in the question stem:

4800/3600 = x/4800
x = 6400

Kudos [?]: 5 [0], given: 35

Intern
Joined: 25 Nov 2017
Posts: 4

Kudos [?]: 0 [0], given: 0

### Show Tags

19 Dec 2017, 23:16
Easy question if ever comes up on GMAT:

We can see every 3 population grew up by 1 unit.

Divide by 400
We get the ratio 9:12

Next equivalent ratio should be (12*4)/3=16

So, 16*400=6400

Sent from my ZUK Z2132 using GMAT Club Forum mobile app

Kudos [?]: 0 [0], given: 0

Re: M01-09   [#permalink] 19 Dec 2017, 23:16

Go to page   Previous    1   2   [ 24 posts ]

Display posts from previous: Sort by

# M01-09

Moderators: chetan2u, Bunuel

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.