Official GRE PowerPrep Arithmetic Excercise

GRE Quant Problem Solving
1

I don’t understand the explanation given here. I have no idea how it can be inferred that the coordinate of C is 1/3+AB+AC.

I tried solving it by making two equations out of it.

(I) AB=CD

and

(II)

CD=1/3BC

Then I tried to express B in terms of C, which if we put in the values for A (1/3) and B(1/2) gives me B=3/2C. Then I got stuck as I tried to substitute for B in the second equation.

Screenshot
Screenshot1462×1174 71.5 KB

2

Excuse me if I am misinterpreting but it seems like you are treating AB as “A times B” rather than “the distance between A and B”.

You are never multiplying any of the values of A, B, C or D. Treat the distances as constants and see if that makes the problem more clear.