Sets

[thementor]

If A ⊆ B, n(A)=42, n(B)=75 find n(A∩B) and n(A U B)
plzz help
my solution
since A is a subset of B then (A U B)=75-42=33
then using this formula
n(A U B)= n(A) + n(B) - n(A ∩ B )
therefore
n(A ∩ B) = 117 -33
=84

 

[smzimran]

If A ⊆ B, n(A)=42, n(B)=75 find n(A∩B) and n(A U B)
plzz help
my solution
since A is a subset of B then (A U B)=75-42=33
then using this formula
n(A U B)= n(A) + n(B) - n(A ∩ B )
therefore
n(A ∩ B) = 117 -33
=84

U means union and ∩ means intersection!!!