Answer:
![a \geq 18](https://img.qammunity.org/2020/formulas/mathematics/high-school/jzys0yppt6veg816eejauf7dk6sg3lnhbn.png)
Explanation:
The question concerns the use of inequalities in correct mathematical language.
When we have the condition "at least", it means something is greater than and equal; when we have the condition "at most", it is lesser than and equal.
In this case, we must use the former condition. Let's denote age with the letter a.
Then, the correct inequality is going to be:
![a \geq 18](https://img.qammunity.org/2020/formulas/mathematics/high-school/jzys0yppt6veg816eejauf7dk6sg3lnhbn.png)