If \(X\) and \(Y\) are two independent events such that \(P (X) = \frac{1}{8}\) and \(P (X ⋃ Y) = \frac{5}{8}\), find \(P (Y)\).

A.

\(\frac{1}{6}\)

B.

\(\frac{4}{7}\)

C.

\(\frac{4}{21}\)

D.

\(\frac{3}{7}\)

Correct answer is B

\(P(X⋃Y)=\frac{5}{8}\)

\(P(X⋂Y)=P(X)\times P(Y)\)

Since X and Y are independent events, the probability of their union (X ⋃ Y) can be calculated as:

\(P(X⋃Y)=P(X)+P(Y)-P(X⋂Y)\)

\(=\frac{5}{8}=\frac{1}{8}+P(Y)-\frac{1}{8}\times P(Y)\)

\(=\frac{5}{8}-\frac{1}{8}=P(Y)-\frac{1}{8}\times P(Y)\)

\(=\frac{1}{2}=P(Y)(1-\frac{1}{8})\)

\(=\frac{1}{2}=P(Y)(\frac{7}{8})\)

\(=P(Y)=\frac{1}{2}÷\frac{7}{8}\)

\(∴P(Y)=\frac{1}{2}x\frac{8}{7}=\frac{4}{7}\)