Answer:
x ≤ 5
y ≤ 8
12x + 6y ≤ 20
Explanation:
First, x ≤ 5 is a constraint because Ronald has enough yarn to make 5 or less hats.
y ≤ 8 is also a constraint because Ronald has enough yarn to make 8 or less scarves.
Lastly, 12x + 6y ≤ 20 is a constraint because Ronald has 20 hours to knit, and it takes 12 hours to knit a hat and 6 hours for a scarf.