If n(A)= 60 , n(AuB) = 120 and
n(AnB)=10, find n(B)
Solution
n(AuB) = n(A) + n(B) - n(AnB)
120 =
60 + n(B) – 10
120 =
60 -10 + n(B)
120 =
50 + n(B)
120 -
50 = n(B)
70
= n(B)
Hence n(B) = 70 answer
TRY THIS…………………………….
If n(A)= 66 , n(AuB) = 120 and
n(AnB) = 30, find n(B).