Chromatic Number:- Minimum number of color needed to mark every vertices of a graph ,but no two adjacent vertices can have same color
QUESTION :1
Let B be RED
then W be Blue G can not be red or blue as then it will be two same color connecting let G YELLOW
R can be BLUE as it is connected with B and G which has no Blue Color(We could have marked with anyother color ,but we need minimum color number)
Right hand @W can again be YELLOW
Inthis way you can progress