Question

in an examination, 50% of the students passed in mathematics and 70% of the students failed in science while 10% students failed in both the subjects. 300 students passed at least one subject. find the total number of students who appeared for the examination if they took the examination in only two subjects.

I want the answer in set language. please do answer fast I've got an exam tomorrow.

Answer 1

A = event that person passes in Maths
B = event that person passes in Science
P(A) = 0.5
P(B) = 0.7
P(A∪B) = probability that person passes in atleast one subject
1-P(A∪B) = probabiliy that person fails in both subjects = 0.1
P(A∪B) = 0.9 = 300/Total number of students
Total number of students = 300/0.9 ≈ 333