Mathematics for IGCSE & O level - Powers And Roots (Section 1 - No. 20)
If n(A ∪ B) = n(C), and the Venn diagram shows n(A ∩ B) = 7, n(A) = 2x, n(B) = 5, n(C) = 8, what is x?
1.5
2
0.5
1
설명
Since n(A ∪ B) = n(C), and n(A ∩ B) = 7, then x must equal 1.5, which makes n(A) 3, but the value 7 and the value 5, added to n(A ∪ B) which is 8, means x must equal 1.5