Solution and Explanation:
(a) Variable Cost ; because the instructor will be paid as per the number of students that would be taught by him.
(b) $5600;
Enrollment fees per student = $210 , Instructor fees per student = $490
Profit per student = $280
Profit from 20 students = 20 multiply $280 i.e $5600
(c) $5600 , 10% ;
Profit from 22 students = 22 multiply with $280 i.e. $6160
[tex]$\%$ change in profit $=(\$ 6160 \text { minus } \$ 5600) / \$ 5600$[/tex] = 10%
(d) $7,200 , 10% ;
Profit from 18 students = 18 multiply with $280 i.e. $5040
[tex]percent change in profit $=(\$ 5040 \text { minus } \$ 5600) / \$ 5600$[/tex] Â = -10%
(e) The only cost charged against the revenue is instructor cost, which is $300 per student. It is a variable cost and changes proportionately will the number of students resulting in proportional increase / decrease in profit with the change in number of students.