Answer: There are 82.5% after school students who are enrolled in his classes.
Step-by-step explanation:
Let the total number of students be 100
Percentage of students who need help in computer science = 30%
So, number of students who need help in computer science = 30
Percentage of students who need help in maths = 70%
So, number of students who need assistance in maths = 70
Of the students who need help,
40% are enrolled in Mr. Ellis's class during the school day,
So, it means 60% are enrolled in his class after the school day.
Number of students who are enrolled in his class after the school day = 60
Number of students who need help in Maths is given by
Of the students that need help in maths, percent of students are enrolled in his class during the day = 25%
So, number of students who need help in maths and enrolled in his class after school hours
Number of students who need help in computer science and enrolled in his class after school hours
Therefore, there are 
students who joined his class after school hours,
Percentage of the after students who are enrolled in Mr. Ellis's classes is given by
Hence, there are 82.5% after school students who are enrolled in his classes.
