Question

a class has 100 students. if 60 know English, 80 knows hindi ,and all the students of the class know either hindi or english or both ,find the number of students who know both the language.

Answer 1

Let,
E=set of students know English
H=set of students know hindi
here,
n (E)=60,n (H)=80,n (H union E)=100,n (H intersection E)=?
therefore, 100=60+80-n (H intersection E)
n (H intersection E)=40
40 students know both the language.