Solving Compound Inequalities

The given diagram shows that the wormfish are found at a depth between $10$ feet and $2000$ feet. If we let $d$ represent the depth at which wormfishes are found, it follows that $d$ must be greater than or equal to $10$ and $d$ must be less than or equal to $2000.$ $$\begin{array}{c}d\ge 10\text{and}d\le 2000\end{array}$$ To graph these inequalities, we will place a closed circle on both $10$ and $2000,$ because $d$ can equal these values. The solution set is shaded as the region between them.