There you go. Updated it.
My reasoning is that from the first two equations I get a relation between the distance to Curnorax and the distance to Smurnorax. C and S standing for the respective distances, I get: C=S/2-150.
Inserting that into my third equation I get:
A(S/2-150)=G(2xS-50) which yields the S of my previous post, which is too small.