Answer:
There are 40 students in the class.
Step-by-step explanation:
We are given the following in the question:
Percentage of class that failed = 15%
Percentage of class that made mistakes but did not fail = 25%
Number of students that got perfect score = 24
Percentage of students that got perfect score =

Let x be the total number of students in the class.
Then, we can write:

Thus, there are 40 students in the class.