Jamey wanted to understand whether students 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 5 3 9 grade 10 8 12 9 grade 11 15 16 10 grade 12 12 6 11 if the principal randomly selects a student in grade 9 from this survey, what is the probability that the student is in favor of extending the school day?

Table

               In favor   OpposedUndecided
Grade 9     5             3               9
Grade 10   8           12               9
Grade 11  15            16              10
Grade 12 12             6               11

Probability = number of positive outcomes / number of possible outcomes

Probability that a student in grade 9 is in favor of extending the school day =

number of students in 9 grade in favor / number of students in grade 9

number of students in 9 grade in favor = 5

number of students in 9 grade = 5 + 3 + 9 = 17

Probability = 5 / 17

5 / 17

Set up a system of equations