City X has a population 8 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?	Choose the correct option
A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 16:1
x= 8y, y= 2*z   X : Y , Y : Z   8 : 1 , 2 : 1   16 : 2 , 2 : 1   So, X : Z = 16 : 1   (16:1)
<result>E</result>
City X has a population 8 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?