Three Radio Stations Decide to Play the Same Song Independently

Short Answer

Three radio stations decide to play the same song independently of one another. They each start playing the song randomly sometime between 12:00pm and 12:25pm.
(a) Find the probability that the song plays for the last time between 12:18pm and 12:22pm.
(b) Find the probability that all three are played between 12:05pm and 12:20pm.