【签过】2012/6/1父母2人B2北京1000# Reunion - 探亲与陪读
t*e
1 楼
就是下面这题，想得绕，有什么简洁的方法来理解，谢谢。
In a recent study of demographics in city A. Bob randomly selected 10,000
mothers and calculated that the average number of kids those mothers have is
X. Independently, Mary randomly selected 10,000 people and calculated that
the average number of siblings those individuals have is Y. Please choose
the relationship between X and Y, and explain why.
(A) X = Y + 1
(B) X > Y + 1
(C) X < Y + 1
In a recent study of demographics in city A. Bob randomly selected 10,000
mothers and calculated that the average number of kids those mothers have is
X. Independently, Mary randomly selected 10,000 people and calculated that
the average number of siblings those individuals have is Y. Please choose
the relationship between X and Y, and explain why.
(A) X = Y + 1
(B) X > Y + 1
(C) X < Y + 1
