4.II.11G
Part IB, 2007
A regular icosahedron has 20 faces, 12 vertices and 30 edges. The group of its rotations acts transitively on the set of faces, on the set of vertices and on the set of edges.
(i) List the conjugacy classes in and give the size of each.
(ii) Find the order of and list its normal subgroups.
[A normal subgroup of is a union of conjugacy classes in .]