Question

If n (x)=12, n (y)=13, n (x union y)= 22. Find n (x intersection y). This is a question from the chapter 'Sets'.

Answer 1

n(x) + n(y) - n(x intersection y) = n(x Union y)
12 + 13 - n (x intersection y)=22
25 - 22 = n(x intersection y)
3 = n(x intersection y)

Answer 2

n(x)=12
n(y)=13
n(x ∪ y)=22
therefore, n(x ∩ y)=n(x)+n(y)-n(x ∪ y)
therefore answer is, n(x∩y)= 12+13-22 = 3