The rate of the reaction between two reactants X and Y can be expressed as $$R = k[X]^2[Y]$$. In an experiment, the initial rate of the reaction was found to be $$R_1$$ when the initial concentrations of X and Y are $$[X_0]$$ and $$[Y_0]$$. Another experiment was performed in which $$[X_0]$$ was taken as $$\frac{1}{2}[X_0]$$. What should be $$[Y_0]$$ in this experiment to get the initial rate as $$0.5R_1$$?