Answer: The coordinates of point B are (19 , 20).
Step-by-step explanation:
The mid point (x,y) of line joining (a,b) and (c,d) is given by :-
(1)
Given : Point A is located at (3,6). The midpoint of line segment AB is point C(11,13).
Let the coordinates of point B are (a,b) m, the according to (1) , we have

Hence, the coordinates of point B are (19 , 20).