No, similar triangles cannot contain a pair of parallel lines. Yes, because || . Yes, because ∠QUR ≅ ∠TUS (vertical angles) and ∠R ≅ ∠S (alternate interior angles).
The answer is 24. it works like this. you subtract 2 from 12 and get 10. then add 5 to 10 to get 15. then subtract 2 from 15 and get 13. 13+5 is 18. and so on