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# What was the percent increase in the population of City K from 1980 to

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Director
Joined: 01 May 2007
Posts: 668
What was the percent increase in the population of City K from 1980 to  [#permalink]

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24 Mar 2008, 13:41
10
36
00:00

Difficulty:

15% (low)

Question Stats:

76% (01:01) correct 24% (00:51) wrong based on 519 sessions

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What was the percent increase in the population of City K from 1980 to 1990 ?

(1) In 1970 the population of City K was 160,000
(2) In 1980 the population of City K was 20 percent greater than it was in 1970, and in 1990 the population of City K was 30 percent greater than it was in 1970.
Director
Joined: 10 Sep 2007
Posts: 717
Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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24 Mar 2008, 14:57
13
7
Statement 1:
Tells us about population in 1970 and nothing else, so this alone is insufficient.

Statement 2:
Tells us that in 1980 population is 20% more than it was in 1970. Say it was x in 1970, then in 1980 it is 1.2x.
Also given that in 1990 population is 30% more than it was in 1970. Say it was x in 1970, then in 1990 it is 1.3x.

Percent Increase from 1980 to 1990 = (1.3x-1.2x)*100/1.2x (Although you don't need to calcluate it, as answer is not required to be filled in anywhere.

##### General Discussion
Senior Manager
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 421
Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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28 Jun 2011, 11:07
4
Let the population of 1970 = 100
so population of 1980 = 120
thus population of 1990 = 130
percentage increase = 10/120*100
ans.D
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Director
Joined: 01 Feb 2011
Posts: 544
Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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28 Jun 2011, 16:10
1
((90 - 80 )/ 80 )*100

1. Not sufficient

we dont know anything about 80 or 90.

2. Sufficient

70 80 90
x 120x/100 130x/100

from this we can easily find out ((80-90)/80 )*100

Intern
Joined: 28 Feb 2011
Posts: 48
Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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28 Jun 2011, 18:51
1
1
B..
Let population in 1970=100
Then, in 1980= 120
in 1990= 130

We can easily find the percent increase from 1980 to 1990 now..
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Intern
Joined: 12 Jul 2016
Posts: 17
Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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08 May 2017, 03:45
Statement 1 is clearly unsufficient since there is no information about 1980 nor 1990.
Statement 2 ables to deduce the solution but only if we have the 1970's population. (unsufficient)
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Re: What was the percent increase in the population of City K from 1980 to  [#permalink]

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05 Aug 2019, 11:35
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Re: What was the percent increase in the population of City K from 1980 to   [#permalink] 05 Aug 2019, 11:35
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