Can anybody solve this question:

The angle of elevation of an aeroplane from a point A on the ground is 60.After a flight of 30 seconds, the angle of elevation changes to 30.If the plane is flying at a constant height of 3600√3 m, find the speed, in km⁄(hour,) of the plane.

why

  let the dist of initial pos from pt on ground = x

dist travelled further = y

tan60= 3600root3/x

x= 3600m

tan30 = 3600root3/y+3600

y = 7200m

dist = 7200m  = 7.2km

time = 30 secs = 30/3600hrs

speed = 7.2 * 100*36/30 = 864 km/hr

is it 240m/sec or 864km/hr

thats absolutely correct.you r the best buddy.