GATE Civil Engineering (CE) 2015 Shift 1 Solved Paper

In a region with magnetic declination of 2°E, the magnetic Fore bearing (FB) of a line AB was measured as N79°50’E. There was local attraction at A. TO determined the correct magnetic bearing of the line, a point O was selected at which there was no local attraction. The magnetic FB of line AO and OA were observed to be S52° 40’E and N50°20’W, respectively. What is the true FB of line AB?