Question

When a student is selected at random from a population of high school students, the

probability the student has a smartphone is .71, the probability the student has a tablet is
.28 and the probability the student has both is .13. What is the probability a student has a tablet given they have a smartphone. Round to the nearest percent

Answer 1

Pr(tablet given smartphone) = 18%

Explanation:

Let:

probability that the student has a smartphone = Pr(smart phone)

Pr(smart phone) =0.71

the probability that the student has a tablet = Pr(tablet)

Pr(tablet) = 0.28

the probability the student has both = Pr(both)

Pr(both) = 0.13

the probability a student has a tablet given they have a smartphone = Pr(tablet given smartphone)

Pr(tablet given smartphone) = Pr(tablet & smartphone)/Pr(smart phone)

Pr(tablet given smartphone) = 0.13/0.71

Pr(tablet given smartphone) = 0.183 = 18.3%

Pr(tablet given smartphone) = 18%