Explanation
Students passed in English = 80%
Students passed in Math's = 85%
Students passed in both subjects = 73%
Then, the number of students who passed at least one subject
= (80+85)-73
= 92%.
[The percentage of students who passed in English and Maths individually, has already included the percentage of students who passed in both subjects. So, We are subtracting the percentage of students who have passed both subjects to find out the percentage of students who at least passed one subject.]
Thus, students failed in both subjects = 100-92 = 8%.