Respuesta :
Answer:
There is a 46.25% probability that she receives a donation.
Step-by-step explanation:
We have to divide these probabilities in 2.
First the probability that each suburb donates.
There is a 60% probability that a person from Belle Meade donates
There is a 55% probability that a person from Oak Hill donates.
There is a 35% probability that a person from Antioch donates.
Now the probability that she calls each suburb.
The probablem states that her list of telephone numbers includes one thousand households from Belle Meade, one thousand from Oak Hill, and two thousand from Antioch. In all, she has 4000 total telephone numbers.
She has 1000 numbers from Belle Maede. So there is a 1000/4000 = 25% probability that she calls a person from Belle Maede.
She has 1000 numbers from Oak Hill. So there is a 1000/4000 = 25% probability that she calls a person from Oak Hill.
She has 2000 numbers from Antioch. So there is a 2000/4000 = 50% probability that she calls a person from Antioch.
What is the probability that she gets a donation?
[tex]P = P_{1} + P_{2} + P_{3}[/tex]
[tex]P_{1}[/tex] is the probability the she randomsly choses a person from Belle Maede and receives a donation. So:
[tex]P_{1} = 0.6*0.25 = 0.15[/tex]
[tex]P_{2}[/tex] is the probability the she randomsly choses a person from Oak Hill and receives a donation. So:
[tex]P_{2} = 0.55*0.25 = 0.1375[/tex]
[tex]P_{3}[/tex] is the probability the she randomsly choses a person from Antioch and receives a donation. So:
[tex]P_{2} = 0.35*0.50 = 0.175[/tex]
[tex]P = P_{1} + P_{2} + P_{3} = 0.15 + 0.1375 + 0.175 = 0.4625[/tex]
There is a 46.25% probability that she receives a donation.