In a class, there are 100 students. Of them, 60 students attend music classes, 40 students attend dance classes, and 20 students attend both the classes. Find the number of students who attend neither of the classes.
The following steps are involved in solving the above problem. Arrange them in sequential order
(A) `n(M cup D)=n(M)+n(D)-n(M cup D) rarr n(M cap D)rarr n(M cup D)=60 + 40 -20 =100 -20 = 80 `
( B) `therefore`Number of students who attend neither of the classes = 100 - 80 = 20
( C) `n(M)=60 ,n(D)=40 and n(M cap D)= 20 ("given")`
(D) Let n(M) be the number of students who attend music classes and n(D) be the number of students who attend dance classes.