Question

Kris wanted to understand whether studentstudents at her school were in favor of an extended school day. She surveyed some students and displayed the results in the table below:

In favor
Opposed
Undecided
Grade 9
6
4
8
Grade 10
10
11
9
Grade 11
12
15
11
Grade 12
15
6
14


If the principal randomly selects a student in grade 10 from this survey, what is the probability that the student is opposed to extending the school day?

Answer 1

The probability should be 36.67% if the number of people in tenth grade who replied 'opposed' is 11 and the principal is only selecting from grade 10.

Answer 2

The probability that the student is opposed to extending the school day is 0.3666 or 36.67% approx.

Explanation:

Arranging the table properly and adding a column of total students.

In favor Opposed Undecided Total students

Grade 9 6 4 8 18

Grade 10 10 11 9 30

Grade 11 12 15 11 38

Grade 12 15 6 14 35

If the principal randomly selects a student in grade 10 from this survey, this means we will only consider grade 10 students.

The probability that the student is opposed to extending the school day is =
`(number of opposed students)/(total number of students)`

There are 11 students who are opposed and total students in grade 10 are 30.

So, probability is :
`(11)/(30)= 0.3666` or 36.67% approx.