Re: On his drive to work, Leo listens to one of three radio stations A, B
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21 Sep 2022, 03:50
On his drive to work, Leo listens to one of three radio stations A, B or C. He first turns to A. If A is playing a song he likes, he listens to it; if not, he turns it to B. If B is playing a song he likes, he listens to it; if not, he turns it to C. If C is playing a song he likes, he listens to it; if not, he turns off the radio. For each station, the probability is 0.30 that at any given moment the station is playing a song Leo likes. On his drive to work, what is the probability that Leo will hear a song he likes?
A. 0.027
B. 0.090
C. 0.417
D. 0.657
E. 0.900
The desired probability is the sum of the following events:
A is playing the song he likes - 0.3;
A is not, but B is - 0.7*0.3=0.21;
A is not, B is not, but C is - 0.7*0.7*0.3=0.147;
\(P=0.3+0.21+0.147=0.657\).
Or: 1-the probability that neither of the stations is playing the song he likes: \(P=1-0.7*0.7*0.7=0.657\).
Answer: D.