Answer: The required probability is 22.5%.
Step-by-step explanation:
Since we have given that
Probability of radio listeners live in Waterville = 0.75
Probability of radio listeners live in Newport = 0.25
Probability of radio station KTBC in Waterville = 0.20
Probability of radio station KTBC in Newport = 0.30
So, using "Multiplication rule of Probability":
Probability that the listener will be tuned in to station KTBC is given by

Hence, the required probability is 22.5%.