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OG City X has a population 4 times

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OG City X has a population 4 times

by AbeNeedsAnswers » Mon Feb 26, 2018 9:12 am

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City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?

A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1

E
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by Brent@GMATPrepNow » Mon Feb 26, 2018 9:26 am
AbeNeedsAnswers wrote:City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?

A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1
One approach is to assign some values that meet the given information

City Y has a population twice as great as the population of City Z
Let's say the population of City Z is 1 person
This means the population of City Y is 2 people

City X has a population 4 times as great as the population of City Y
If the population of City Y is 2 people, then the population of City X is 8 people

So, the ratio of the population of City X to the population of City Z = 8 to 1

Answer: E

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by Scott@TargetTestPrep » Wed Feb 28, 2018 10:36 am
AbeNeedsAnswers wrote:City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?

A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1
We are given that City X has a population 4 times as great as the population of City Y and that City Y has a population twice as great as the population of City Z.

If we let the population of City X = x, the population of city Y = y, and the population of city Z = z, we can create the following equations:

x = 4y

and

y = 2z

We need to determine the ratio of the population of City X to the population of City Z, or x/z. We see that:

x = 4y

x = 4(2z)

z = 8z

x/z = 8

Thus, the ratio is 8 : 1.

Answer: E

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by [email protected] » Wed Apr 18, 2018 8:07 pm
Hi All,

We're told that City X has a population 4 TIMES as great as the population of City Y, which has a population TWICE as great as the population of City Z. We're asked for the ratio of the population of City X to the population of City Z. Based on the design of this question - and the design of the answer choices, we can get the correct answer without doing much math at all.

To start, we know that the population of City X is 4 TIMES as great as that of City Y and City Y's population is GREATER than that of City Z. When comparing City X's population to City Z's, we know that City X's population has to be MORE than 4 TIMES greater than City Z's... and there's only one answer that would account for that type of difference..

Final Answer: E

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