Answer 1

We know that the coordinates of the centroid of a triangle whose vertices are 

`(x_1,y_1),(x_2,y_2) (x_3,y_3)`are 

`((x_1+x_2+x_3)/3,(y_1+y_2+y_3)/3)`  

so, the coordinates of the centroid of a triangle whose vertices are 

(1,4),(-1,-1) and (3,-2) are `((1-1+3)/3,(4-1-2)/3)` 

`=(1,1/3)`