Question

if A={1,2,3,4,5}, B={4,6,7} then verify n(AUB)=n(A)+n(B)-n(A∩)​

Answer 1

(AUB) = {1, 2,3,4,5,6,7}

n(A)= 5

n(B)= 3

-n(A intersection B) = 6