8/15 is the probability to call a person from school.
Explanation:
The given information are,
Joel is going to call one person from his contacts at random.
The total number of contacts he has = 30 contacts.
Out of those 30 contacts, 16 contacts are the people he met at school.
The probability is to find the call to a person from school.
We already know that, 16 contacts are the people from his school.
P(call a person from school) = No.of school contacts / Total contacts
⇒ 16/30
⇒ 8/15
Therefore, the probability to call a person from school is 8/15.