Surface area is:
[tex]W=width[/tex]
[tex]L=length[/tex]
[tex]H=height[/tex]
[tex]S=2*(L*W+L*H+W*H)[/tex]
replacing the values
[tex]250=2*(8*W+8*1+W*1)[/tex]
[tex]250=2*(8*W+8+W)[/tex]
[tex]250=2*(9*W+8)[/tex]
dived each member by 2
[tex]125=9W+8[/tex]
[tex]9W=125-8[/tex]
[tex]9W=117[/tex]
[tex]\boxed{\boxed{W=13~unit~of~measure}}[/tex]
The volume of a rectangular prism is
[tex]V=L*H*W[/tex]
[tex]V=8*1*13[/tex]
[tex]\boxed{\boxed{V=104~unit~of~volume}}[/tex]