Question

a polyhedron has 18 vertices and 12 face . how many edges does it have

Answer 1

f+v-e=2
12+18-e=2
30-e=2
-e=2-30
-e=-28
e=28

Answer 2

Hii,
We know that according to Euler's formula,
F+V=E+2 (Where F=faces, V=vertices, E=Edges)
But note that this formula is only applicable to polyhedrons.
Now,
F=12
V=18
Putting these in formula,
12+18=E+2
30=E+2
E=30-2
E=28
So ur answer is 28.
Hope it helps you