Gabriel needs to order some new supplies for the restaurant where he works. The restaurant needs at least 587 knives. There are currently 387 knives. If each set on sale contains 20 knives, write an inequality representing s, the number of sets of knives Gabriel should buy.

The number of knives needed by the restaurant is 587 - 387 = <<587-387=200>>200 knives.

Each set on sale contains 20 knives, so the number of sets Gabriel should buy is s = 200/20 = <<200/20=10>>10 sets.
Therefore, the inequality representing s is s ≥ 10. Answer: \boxed{s \geq 10}.

To represent the number of sets of knives Gabriel should buy, we need to find the number of sets, s.

The number of knives Gabriel needs to order is 587 - 387 = 200 knives.

Since each set contains 20 knives, the number of sets Gabriel should buy is s = 200 / 20.

Therefore, the inequality representing the number of sets of knives Gabriel should buy is s ≥ 200 / 20.