SETS 7

If n(A)= 80 , n(AuB) = 200 and n(AnB)=20, find n(B)

Solution

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

  200     = 80 + n(B)  – 20

  200     = 80 -20 + n(B) 

  200     = 60 + n(B) 

  200 - 60        = n(B)

  140        = n(B)

Hence n(B) = 140 answer

TRY THIS…………………………………… 

If n(A)= 99 , n(AuB) = 160 and n(AnB)=40, find n(B)