Here, F = 10, E = 20 and V = 15
We have:
              F + V - E = 2
∴           10 + 15 - 20 = 2
or               25 - 20 = 2
or                  5 = 2 which is not true
i.e. Â Â Â Â Â Â Â Â Â Â Â
   Thus, such a polyhedron is not possible.