Find the number of vertices of a polyhedron that has 12 faces and 30 edges

20

Step-by-step explanation:

Euler's formula for polyhedra states that

F + V - E = 2

where F is faces, V is vertices and E is edges

Here F = 12, E = 30, thus

12 + V - 30 = 2, that is

V - 18 = 2 (add 18 to both sides)

V = 20 ← number of vertices