Question

N (a-b)=18 , n (a u b ) = 70 , n ( a n b ) = 25 . find n (b)

Answer 1

Answer:

n(a) = n (a-b) + n (a n b )

n (a u b ) = n(a) + n(b) - n (a n b )  

n (a u b ) = n (a-b) + n (a n b ) + n (b) - n (a n b )

n (a u b ) = n(a-b) + n(b)

70 = 18 + n (b)

n (b) = 70-18

n (b) = 52