At the starting of 2012, 60% of the population of Town Y lived in the north and the rest lived in the south. During the year 2012, the population of Town Y grew by 5.5%. If the population in the north grew by 4.5%, by how much did the population in the south grow?	Pick one.
A) 7%
B) 9%
C) 1%
D) 1.5%
E) 3.8%
Here I prefer the weighted average method over dealing with creating and solving the algebraic expression:   Ratio of population in the Town Y -North:South :: 60%:40% = 3:2   Mean growth = 5.5%   South Growth: 4.5%   North Growth = ??   North-------------7%verage--------------South   4.5% __(2n)_____5.5%_____(3n)_____??   Since:   4.5 + 2n = 5.5   n = 1/2 (this is the multiplier of the ratio)   Therefore:   South = 5.5 + 3n   South = 5.5 + 3(0.5) = 7%
<result>A</result>
At the starting of 2012, 60% of the population of Town Y lived in the north and the rest lived in the south. During the year 2012, the population of Town Y grew by 5.5%. If the population in the north grew by 4.5%, by how much did the population in the south grow?