Question

IF X AND Y ARE TWO FINITE SETS SUCH THAT N(X)=9, N(X∩Y)=4 AND N(X∪Y)=15,THEN N(Y) IS? (WORKING OUT PLEASE)

Answer 1

It is given that:

n(X)=17,n(Y)=23,n(X∪Y)=38

n(X∩Y)=?

Using the formula

n(X∪Y)=n(X)+n(Y)−n(X∩Y)

∴38=17+23−n(X∩Y)

⇒n(X∩Y)=40−38=2

∴n(X∩Y)=2

Answer 2

Answer:

I think N(Y) = 6

because the N(X)=9 - 4 =5

and x union y = 15

so 15-4 =11

so N(Y) = 6

if this answer is correct mark me as brainlist!!