You count the number of vertices in the polygon that forms the base. The prism has twice as many vertices.
24 vertices
2n.
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges. 1 base, 8 vertices
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges.
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges. 10 vertices
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges. 16 vertices
9
5
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges.
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges.
A prism with an n-sided base will have 2n vertices. A pyramid with an n-sided base will have n + 1 vertices. 6, 4, 8 and 5 vertices respectively.