Let R be a rectangle given by the lines $x=0, x=2, y=0$ and $y=5$. Let A$(\alpha,0)$ and B$(0,\beta),\alpha\in[0,2]$ and $\beta\in[0,5]$, be such that the line segment AB divides the area of the rectangle R in the ratio 4 : 1. Then, the mid-point of AB lies on a :