Question

in a survey of students 60% were in high school in 40% were in middle school of the high school students 30% had visited a foreign country if a survey of student is selected at random what is the probability that the student is in high school and has visited a foreign country?

Answer 1

0.18

Explanation:

Given: 60% students were in high school, 40% were in middle school and of the high school students, 30% had visited a foreign country

To find: probability that the student is in high school and has visited a foreign country

Solution:

Let x denotes total number of students

Number of students in high school = 60% of x =
`(60)/(100)x`

Number of students in middle school = 40% of x =
`(40)/(100)x`

Number of students who are in high school and have visited foreign country = 30% of Number of students in high school =
`(30)/(100)((60)/(100))x=(18)/(100)x`

Probability that the student is in high school and has visited a foreign country = Number of students who are in high school and have visited foreign country/ Total number of students =
`((18)/(100)x)/(x)=(18)/(100)=0.18`