Answer
$8\frac{1}{8}$ inches
Work Step by Step
Let $d$ be the distance a spring stretches.
Let $w$ be the weight.
$d=kw$
$d=5; w=40$
$5=k(40)$
$k=\frac{1}{8}$
$d=\frac{1}{8}w$
$w=65$
$d=\frac{1}{8}(65)$
$d=\frac{65}{8}=8\frac{1}{8}$ inches