We are given
[tex]1\leq x\leq 3[/tex]
So, smallest x-value is 1
[tex]3\leq y\leq 5[/tex]
So, smallest y-value is 3
now, we can find least possible average
so, least possible average value is
[tex]=\frac{1+3}{2}[/tex]
[tex]=\frac{4}{2}[/tex]
[tex]=2[/tex]
So,
The least possible average value is 2.........Answer