I am having trouble with the following questions:

1.A plane flying horizontally at an altitude of 2 miles is heading directly toward a radar station. The radar station is changing to be -300 mph when the plane is s=3 miles from the station. Find the speed of the plane (relative to the ground) at this point.

b. Find the rate of change of the angle of elevation (in radians per minute) from the station tho the plane at the same point.

c.A water trough is 2 feet deep and 10 feet long, and it has an isosceles trapezoidal cross section with base lengths 2 feet and 5 feet. If water enters the trough at the rate of 10 cu ft/ min, how fast is the water level rising when the water is 1/5 foor deep?