In a class of 40 students, 32 offer Mathematics, 24 offer Physics and 4 offer neither Mathematics nor Physics. How many offer both Mathematics and Physics?

Answer Details

No of students in class = 40
(M) No of students who offer mathematics = 32 - x
(P) No of students who offer physics = 24 - x
(N) No of students who offer neither mathematics nor physics = 4
(B) No of student who offer both = x
Total no of students = M + P + N + B
40 = 32 - x + 24 - x + 4 + x
40 = 32 + 24 + 4 - x
40 = 60 - x
x = 60 - 40
x = 20