A small plane is flying due east at a constant altitude of 3 km and constant speed of 120 km/h. It is approaching a small control tower that lies to the south of the planes path. At time t the plane is on a bearing of 300 degrees from the tower, and elevated 4.5 degrees. How long does it take for the plane to be due north of the tower, and what is it's angle of elevation from the tower at this time?

pur-new-sol