A boy standing in the middle of a field, observes a flying bird in the north at an angle of elevation fo 30 degree. and after 2 min, he observes the same bird in the south at an angle of elevation o f60 degree. If the bird flies all along in a straight line at a height of 50root3 m, then its speed in km/h is?
Ans)
tan30=50√3/x
1/√3=50√3/x
150=x
√3=50√3/y
y=50
total distance covered =x+y=200m
.2km
time=2/60hr
speed=6km/hr