In a mosaic plot representing a contingency table of variables $X$ (2 levels) and $Y$ (3 levels), the total area of the plot is 1. If $P(X=x_1) = 0.4$ and $P(Y=y_1 | X=x_1) = 0.5$, what is the area of the rectangle representing the intersection $(x_1, y_1)$?