A truck is painting traffic lines along a highway. The truck paints 8 miles of lines in 3 hours. At that rate, how many miles can the truck paint in 12 hours?

The answer would be 32 miles (I think) if you set up a proportion you should get this answer.

32 miles. I knew that 3 hours I went 8 miles. Then if I went 6 miles that means I went 16 miles. Then if I went 9 hours then I would have gone 14 miles. If I went 12 hours I would have gone 32 miles. I added three (3) to every hour until I got to 12, and I add eight (8) to every mile.