) + n ( B ) – n ( A ∩ B ) = + – = . EXERCISE . . If X and Y are two sets such that n ( X ) = , n ( Y ) = and n ( X ∪ Y ) = , find n ( X ∩ Y ).
. If X and Y are two sets such that X ∪ Y has elements, X has elements and Y has elements ; how many elements does X ∩ Y have? . In a group of people, can speak Hindi and can speak English.
How many people can speak both Hindi and English? . If S and T are two sets such that S has elements, T has elements, and S ∩ T has elements, how many elements does S ∪ T have? .
If X and Y are two sets such that X has elements, X ∪ Y has elements and X ∩ Y has elements, how many elements does Y have? . In a group of people, like coffee, like tea and each person likes at least one of the two drinks. How many people like both coffee and tea?
. In a group of people, like cricket, like both cricket and tennis. How many like tennis only and not cricket? How many like tennis?
. In a committee, people speak French, speak Spanish and speak both Spanish and French. How many speak at least one of these two languages?