SETS 2

If n(A)= 30 , n(AuB) = 100 and n(AnB)=10, find n(B)

Solution

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

  100     = 30 + n(B)  – 10

  100     = 30 -10 + n(B) 

  100     = 20 + n(B) 

  100 - 20        = n(B)

  80        = n(B)

Hence n(B) = 80 answer

TRY THIS…………………………….

If n(A)= 60 , n(AuB) = 110 and n(AnB) = 30, find n(B).