Step 1:

Let $X$ be the random variable denoting the numbers of ships out of 500 that return safely to the port.

The probability of a ship not returning safely=$\large\frac{1}{10}$$=q$

$\therefore p=1-\large\frac{1}{10}=\frac{9}{10}$

$X\sim B(500,\large\frac{9}{10})$

Step 2:

The mean=np

$\qquad\quad\;\;=500\times \large\frac{9}{10}$

$\qquad\quad\;\;=450$

The standard deviation =$\sqrt{npq}$

$\qquad\qquad\qquad\qquad=\sqrt{500\times \large\frac{9}{10}\times \frac{1}{10}}$

$\qquad\qquad\qquad\qquad=\sqrt{45}$

$\qquad\qquad\qquad\qquad=3\sqrt{5}$