Question

A n-faced regular polyhedron consists of 2n edges and (2n-4) vertices. Find n .

Answer 1

We could use Euler's polyhedron formula:

$F=n\qquad\qquad\text{(Faces)}\\\\E=2n\qquad\qquad\text{(Edges)}\\\\V=2n-4\qquad\qquad\text{(Vertices)}\\\\\\V-E+F=2\\\\2n-4-2n+n=2\\\\-4+n=2\qquad|+4\\\\\boxed{n=6}$