Question

Bruce is going to call one person from his contacts at random. He has 25 total contacts. 20 of those contacts are from his neighborhood. What is P(call a person not from his neighborhood)

Answer 1

Answer: 1/5

Explanation:

Answer 2

P(call a person not from his neighborhood) =
`((1)/(5) )`

Explanation:

Here, the total number of contacts in the list if Bruce = 25 contacts

The total number of neighbors in the contact = 20 people

Now, let E: Event of calling a person from his neighborhood

So, P(E) =
`\frac{\textrm{Total Favorable Outcomes}}{\textrm{Total Outcomes}} = (20)/(25) = ((4)/(5))`

So, the probability of calling a person from his neighborhood is
`((4)/(5) )`

⇒P(E) =
`((4)/(5) )`

Now,as we know: P(E) + P(not E) = 1

So, the probability of NOT calling a person from neighborhood

= 1 - probability of calling a person from his neighborhood

`= 1 - ((4)/(5)) = (5-4)/(5) = ((1)/(5))`

⇒P( not E) =
`((1)/(5) )`

Hence, P(call a person not from his neighborhood) =
`((1)/(5) )`