Television and radio waves reflecting from mountains or airplanes can interfere with the direct signal from the

Question:

Television and radio waves reflecting from mountains or airplanes can interfere with the direct signal from the station.
(a) What kind of interference will occur when 75-MHz television signals arrive at a receiver directly from a distant station, and are reflected from a nearby airplane 118m directly above the receiver? Assume ½ λ change in phase of the signal upon reflection.
(b) What kin of interference will occur if the plane is 22m closer to the receiver?