Given that in a ΔABC, Ellen house lies at vertex A and bunkhouse is put somewhere along BC, let it be D.
Please refer the diagram attached.
We are also given that D must be placed such that
holds true.
Let us re write the above equation such that CD and BD lie on one side.
That is

Which is nothing but angle bisector theorem.
Hence AD must bisect the angle A then only the given condition will hold true.