Current Electricity: JEE Main 2026 Physics question

Two known resistances of $R\,\Omega$ and $2R\,\Omega$ and one unknown resistance $X\,\Omega$ are connected in a circuit as shown in the figure. If the equivalent resistance between points $A$ and $B$ in the circuit is $X\,\Omega$, then the value of $X$ is ______ $\Omega$.