Concept: The question tests on the application of absolute value.

Solution :

Let the points be R,S,T and they have coordinates -a, b, c respectively.

r, s, t are the absolute values of the coordinates -a,b,c respectively.

With R being on the negative side of the number line would have, 

r=|-a|= -(-a)  

=>  -a  (the coordinate in context)= -r  

s = |b| = b

t = |c| = c

Thus the coordinates -a,b,c in terms of r, s, t are -r, s ,t respectively.

Hence average of the coordinates -a, b, c  =   -r + s + t /3  (Option e)

Pls note that the question asks you of the average of the coordinates