5. Lei Lei went to buy instant noodles, handing over a 100 yuan note to the boss. After giving her the change, the boss said to her: “You only gave me 1 note, but I gave you 16 notes, plus instant noodles worth 5 yuan, you really got a great deal!” If the change the boss gave Lei Lei was either 10 yuan or 5 yuan notes, then among these 16 notes, $\qquad$ are 10 yuan notes.