sounds like one drunk hitch hiker.
well, total north displacement = -6+5+12=11km north
total east displacement=4+3-11=-4=4km west
(11^2+4^2)^0.5=11.7km he has to walk back.
angle from horizontal=Sin^-1(11/11.7)=70.08 degrees or 160.08 from north if ur doing it like that.
