Question

In a class 80 students passed and the rest failed if 80% of the students fail, f8nd the number of students in a class

Answer 1

total students = x
passed = 80
failed = x - 80
failed% = 80%
now
((x - 80)÷x) × 100 = 80
(x-80)÷x = 8÷10
x-80 = (4÷5)×x
5x - 400 = 4x
x = 400
total students = 400

Answer 2

80% of the students are failed that mean 20% of students passed. 80 students passed means 400 students in the class.
so that the answer is 400 students in the class.