the change is the dog's weight is -8 1/3 pounds in 6 weeks
that is
[tex]-8\frac{1}{3}=\frac{-25}{3}[/tex]6 weeks weight change is - 25/3
so for 1 week
[tex]\frac{\frac{-25}{3}}{6}=\frac{-25}{6\times3}=\frac{-25}{18}[/tex]so weight change is each week is - 25 / 18
[tex]\frac{-25}{18}=-1\frac{7}{18}[/tex]so the answer is -1 7/18 pounds.