the table below:
Grade In favor Opposed Undecided Total
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,
the probability that the student is opposed to extending the school day
P ( student in grade 10 is opposed)= Number of student in opposed(grade10) / total number of students in grade 10
Number of student opposed who is in grade10 = 11
total number of students in grade 10 = 30
P( student in grade 10 is opposed)= 
= 0.37
the probability that the student is opposed to extending the school day= 0.37
The answer to 8 + 11 is 19
Some parts are missing in the queston. Find attached the picture with the complete question
Answer:

Explanation:
Let's put the information in a table step-by step.
(number of remaining students)
Juniors Seniors
Condition
- Twice juniors as seniors 2(S - 15)
- 3/4 of the juniors left 1/4×2(S - 15)
- 1/3 of seniors left 2/3×(S - 15)
At the end, there were 8 more seniors than juniors:
- 2/3×(S - 15) - 1/4×2(S - 15) = 8
Now you have obtained one equation, which you can solve to find S, the number of senior students, and then the number of junior students.
Solve the equation:



- Addtion property of equalities:


- Division property of equalities:

That is the number of senior students that came out to the information meeting, but the number of students remaining to perform in the school musical is (from the table above):

Just substitute S with 153 fo find the number of students that remained to perfom in the musical:

