The radii of the frustum of a right circular cone are in the ratio 2 : 1. What is the ratio of the volume of the frustum of the cone to that of the whole cone?

The radii of the frustum of a right circular cone are in the ratio 2 :

1.	The radii of the frustum of a right circular cone are in the ratio 2 : 1. What is the ratio of the volume of the frustum of the cone to that of the whole cone?
A.	1 : 8
B.	1 : 4
C.	3 : 4
D.	7 : 8
Answer» E.