According to a recent Pew Research poll, 75% of millenials (people born between 1981 and 1995) have a profile on a social networking site. Let X = the number of millenials you ask until you find a person without a profile on a social networking site. What is the probability that you must ask 20 people to find one person without a social networking site?

0.11% probability that you must ask 20 people to find one person without a social networking site

Step-by-step explanation:

We have these following probabilities:

75% probability that a millenial has a profile in a social netwok site.

25% probability that a millenial does not have a profile in a social network site.

What is the probability that you must ask 20 people to find one person without a social networking site?

The first 19 people have a social network site, each with a 75% probability.

The 20th person does not have a profile, with a 25% probability.

So

0.11% probability that you must ask 20 people to find one person without a social networking site