polyhedron help: even a good clue will get best?

Question

okay, i've been working in circles on this for a while.

considering Euler's formula where V - E + F =2

A polyhedron has 20 faces that are hexagons and p faces that are pentagons with no additional faces. Three faces/edges meet at each vertex.

a) in terms of p, determine the number of edges
b) in terms of p, determine the number of vertices
c) determine the value of p

Answer 1

i think the given data is insufficient to find p or anything about the p.