An FM broadcast receiver in a car is tuned to a radio station at a frequency of 100 MHz. The vehicle is traveling at a speed of 30 km/h in an urban area. You can assume there is no direct line of sight to the transmitter and the angle-of-arrival distribution is uniform. The mean signal level is -70 dBm. The FM receiver output has unacceptable quality (has a low SNR or "fades") when the signal level is below -85dBm. (a) What fraction of the time is the signal level acceptable? (b) How often does the signal "fade"? (c) What is the mean duration of each such fade?