GS. 4 If the line $5 x+2 y-100=0$ has $d$ points whose $x$ and $y$ coordinates are both positive integers, find the value of $d$.
$\begin{array}{l}(x, y)=(18,5),(16,10),(14,15),(12,20),(10,25),(8,30),(6,35),(4,40),(2,45) \\ d=9\end{array}$