An inequality can be formed by simply translating the problem statement to numerical expressions.
From the problem we know that
added with 
hours should be equal or greater than 
(helpful insight from the keyword "at least"). Therefore, it's inequality would look like:
(>= is used instead of ≥ for constraints in formatting)
The inequality above best models the situation.
From the problem we know that
The inequality above best models the situation.
