Question

Which equation gives the number of elements in the complement of event \(A\)?

Options

• \(n(A') = n(A) - n(S)\)

• \(n(A') = 1 - n(A)\)

• \(n(A') = n(S) - n(A)\)

• \(n(A') = n(A) + n(S)\)

Answer 1

The complement contains all elements of \(S\) except those already in \(A\). Subtracting \(n(A)\) from \(n(S)\) therefore gives \(n(A')\).