Respuesta :
The probability that she asks 21 adults total to find the first one that does not own a cell phone is (0.91)²⁰(0.09).
Number of adults having cell phones =91%
Number of adults having cell phones =9%
What is probability?
Probability is the measure of the likelihood of an occurrence.
The probability that she asks 21 adults total to find the first one that does not own a cell phone = the probability that the first 20 adults have a cell phone and the 21st adult does not have a cell phone.
The probability that an adult has a cell phone =0.91
The probability that the first 20 adults have a cell phone = (0.91)²⁰
The probability that the 21st adult does not have a cell phone = 0.09
So, total probability = (0.91)²⁰(0.09)
Hence, The probability that she asks 21 adults total to find the first one that does not own a cell phone is (0.91)²⁰(0.09).
To get more about probability visit:
https://brainly.com/question/24756209