Convex Hull problem

if we given convex hull boundry points and asks to find number of (x,y) points in convex hull then how to find it?

first of all , all the given point will lie inside the convex hull due to definition.
secondly number points that will lie on the convex hull is the sizeof the vector hull.

No, I talk about different question, here is the link of that,

Hello sir , how to solve this type of questions ??