If x and y are inversely proportional,

Since $x$ and $y$ are inversely proportional, $x y$ must be a constant.

Therefore, $8 \times y_{1}=x_{1} \times 4=16 \times 5=x_{2} \times 2=80 \times y_{2}$

Now, $16 \times 5=8 \times y_{1}$

$\Rightarrow \frac{80}{8}=y_{1}$

$\therefore y_{1}=10$

$16 \times 5=x_{1} \times 4$

$\Rightarrow \frac{80}{4}=x_{1}$

$\therefore x_{1}=20$

$16 \times 5=x_{2} \times 2$

$\Rightarrow \frac{80}{2}=x_{2}$

$\therefore x_{2}=40$

$16 \times 5=80 \times y_{2}$

$\Rightarrow \frac{80}{80}=y_{2}$

$\therefore y_{2}=1$

Hence, $y_{1}=10, x_{1}=20, x_{2}=40$ and $y_{2}=1$