you and your brother have been kidnapped by a mad kidnapper. He handcuffed you (hands and legs), put a gag over your mouth (and tightened it tightly), put a cloth over your eyes so you can't see anything, and connected the long chain to the chain on the handcuffs at your legs with a small padlock, and the other end hooked the chain to the bottom of the transparent tank. He locked your brother in a small white room with a window overlooking the room with a small transparent tank in the middle and he can see you in the tank... *The kidnapper says to your brother through the loudspeaker in the room he is in: "I will ask you 5 questions, if you answer one of them incorrectly... the trapdoor under your sister will fall... she will be in the water and the chain will pull her to the bottom and she will not will be able to surface, but if you answer all 5 questions correctly, I will let you go , Do you understand me?"