Answer:
500 students appeared in the examination.
Explanation:
Each event represents a set in the Venn diagram, and we use it to find the desired values.
I am going to say that:
Event A: Passed in English.
Event B: Passed in Science.
80% passed in English
This means that
.
75% passed in Science
This means that

5% failed in both subjects.
This means that 100% - 5% = 95% passed at least one of these subjects, so
.
Proportion that passed both subjects:
This is

These percentages are related by the following equation:

So

Number of students in class:
60% of the total number t passed both subjects. This is equals to 300. So



500 students appeared in the examination.