Probability

\(\mathrm{A}\) and \(\mathrm{B}\) are independent events with \(\mathrm{P}(\mathrm{A})=\frac{1}{4}\) and \(\mathrm{P}(\mathrm{A} \cup \mathrm{B})=2 \mathrm{P}(\mathrm{B})-\mathrm{P}(\mathrm{A})\), then \(\mathrm{P}(\mathrm{B})\) is