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Last Updated on May 10, 2023
GMAT OFFICIAL GUIDE PS
Solution:
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.
To determine the ratio, we can get both x and z in terms of y, so we have:
x = 4y and z = y/2.
We can substitute 4y for x and y/2 for z in the ratio x/z:
(4y)/(y/2) = (4y)(2/y) = 8.
Thus, the ratio is 8 : 1.
Answer: E
