16. Eleven points are marked from left to right on a straight line. The sum of all the distances between the first point and the other points is $2018 \mathrm{~cm}$. The sum of all the distances between the second point and the other points, including the first one, is $2000 \mathrm{~cm}$. What is the distance between the first and second points?
A $1 \mathrm{~cm}$
B $2 \mathrm{~cm}$
C $3 \mathrm{~cm}$
D $4 \mathrm{~cm}$
E $5 \mathrm{~cm}$
16. B Let the distance between the first two points be $x \mathrm{~cm}$. Consider the other nine points. The sum of their distances from the first point is $(2018-x) \mathrm{cm}$ and the sum of their distances from the second point is $(2000-x) \mathrm{cm}$. Also, for each of these nine points, its distance from the second point is $x \mathrm{~cm}$ less than its distance from the first point. Therefore, when we total the distances over the nine points, we obtain $9 x=(2018-x)-(2000-x)$ and hence $9 x=18$. Therefore $x=2$ and so the distance between the first and second points is $2 \mathrm{~cm}$.