SETS 2

If n(B)= 90 , n(AuB)=120, n(AnB)=50, find n(A).

Solution

n(AuB) = n(A) + n(B) - n(AnB)

     120 = n(A)  + 90 - 50

     120 = n(A)  + 40      

     120 - 40 = n(A) 

      80 = n(A) 

Hence n(A) = 80 answer

TRY THIS.................

If n(B)= 70 , n(AuB)=130, n(AnB)=30, find n(A).