Mathematics for IGCSE & O level - Powers And Roots (Section 1 - No. 14)
Which of the following statements are correct regarding sets P, Q, and R if Q ⊆ P, Q ∩ R = ∅, and P ∩ R ≠ ∅?
P ∪ Ø = ∅
R ⊆ Q
R is not a subset of Q
n(R ∩ Q) = n(∅)
Forklaring
If Q is a subset of P (Q ⊆ P), and Q and R have no intersection (Q ∩ R = ∅), and P and R do have an intersection (P ∩ R ≠ ∅), then R cannot be a subset of Q because it shares nothing in common with Q, and the intersection of R and Q is an empty set.