The population of a certain country X

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The population of a certain country X

by BTGmoderatorDC » Wed Feb 07, 2018 12:21 am
The population of a certain country X is 120,108,000 and its land area is 2,998,000 square kilometers. The population of another country Y is 200,323,000 and its land area is 7,899,000 square kilometers. The population density is defined as the population per square kilometer of land area. The population density of country X is approximately what percent greater or lesser than that of country Y?

(A) 60%
(B) 50%
(C) 45%
(D) 37%
(E) 15%

What is the best solution in this?

OA A

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by GMATGuruNY » Wed Feb 07, 2018 4:15 am
lheiannie07 wrote:The population of a certain country X is 120,108,000 and its land area is 2,998,000 square kilometers. The population of another country Y is 200,323,000 and its land area is 7,899,000 square kilometers. The population density is defined as the population per square kilometer of land area. The population density of country X is approximately what percent greater or lesser than that of country Y?

(A) 60%
(B) 50%
(C) 45%
(D) 37%
(E) 15%
Density of X = (population)/(square kilometers) = (120,108,000)/(2,998,000) ≈ (120,000,000)/(3,000,000) = 120/3 = 40.

Density of Y = (population)/(square kilometers) = (200,323,00)/(7,899,000) ≈ (200,000,000)/(8,000,000) = 200/8 = 25.

The population density of country X is approximately what percent greater or lesser than that of country Y?
Percent increase from Y to X = Difference/Smaller * 100 = (40-25)/25 * 100 = 15 * 4 = 60.

The correct answer is A.
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by Jeff@TargetTestPrep » Fri Feb 09, 2018 10:12 am
lheiannie07 wrote:The population of a certain country X is 120,108,000 and its land area is 2,998,000 square kilometers. The population of another country Y is 200,323,000 and its land area is 7,899,000 square kilometers. The population density is defined as the population per square kilometer of land area. The population density of country X is approximately what percent greater or lesser than that of country Y?

(A) 60%
(B) 50%
(C) 45%
(D) 37%
(E) 15%
To simplify the numbers, let's round each number to number of millions.

Thus, the population density of country X is about 120/3 = 40.

The population density of country Y is about 200/8 = 25.

Now we can use the percent change formula:

(40 - 25)/25 x 100%

15/25 x 100% = (15 x 4)% = 60 %

Answer: A

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