two sets A and B are such that n(AuB) =21 and n(AnB) =7 , also n(A'nB') =9 find n(AnB)' - Maths - Sets

Question

two sets A and B are such that n(AuB) =21 and n(AnB) =7 , also
n(A'nB') =9 find n(AnB)'

Anuradha Sharma · Accepted Answer

As we know that nA'∩B'=nA∪B'=U-nA∪B
Here
nA∪B=21 and nA∩B=7,So using equation 1 we get, U-nA∪B=nA'∩B'=9or U = 9+nA∪B=21+9=30Now nA∩B'=U- nA∩B=30-7=23

two sets A and B are such that n(AuB) =21 and n(AnB) =7 , also n(A'nB') =9 find n(AnB)' .