A regular polyhedron has 30 edges and 12 vertices. How many faces does it have?

There are several information's of immense importance already given in the question. Let us write them down first

Number of edges of the regular polyhedron (E) = 30

Number of vertices of the regular polyhedron (V) = 12

Let us assume the number of faces of the regular polyhedron = F

Then

V - E + F = 2

12 - 30 + F = 2

f - 18 = 2

F = 20

From the above deduction, it can be easily concluded that the number of faces of the regular polyhedron is 20.