Constructing planar version of given graph is quite time consuming. We can solve such questions quickly using the relation :
If E is the number of edges and V is the number of vertices, and E<= 3(V-2), graph is planar, otherwise it is Not Planar.
- A) V=4; E=6; 3*(V-2)=3(4-2)=6=E //Planar
- B) V=8; E=12 3*(V-2)=3(8-2)=18 E=12<18 //Planar
answer : Both A and B are planar