Question

If A, B are disjoint set such that n(A) =4 and n(AUB) =7 then n(B) ___​

Answer 1

Answer:

firstly tell what is the value of n(AnB)

Answer 2

Answer:

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

7 = 4+n(B)-0

7-4 = n(B)

n(B) = 3