Logic Riddles

Question: How do you tell if a snake is venomous or not?

Question: 28th Feb, 2015 Josh went to rob a bank. He threatened to kill the cashier if he didn't open the vault. The cashier told him the vault is not opened with keys but with a password. You can't kill me since I'm the only one who knows the password and everyday the password is different. Josh shot the cashier, entered the password, opened the vault and stole all the money. What is the password?

Question:

You have a large number of friends coming over and they all get thirsty. Your first friend asks for 1/2 a cup of water. Your second friend asks for 1/4 a cup of water. Your third friend asks for 1/8 a cup of water, etc.

How many cups of water do you need to serve your friends?

Question: As I was going to St. Ives,
I met a man with seven wives,
Each wife had seven sacks,
Each sack had seven cats,
Each cat had seven kits:
Kits, cats, sacks, and wives,
How many were there going to St. Ives?

Question: At the beginning of the first day of school there was a dead boy found inside of a classroom. They found 3 suspects: The janitor, the teacher and one of the boy's classmates. The janitor claims that he was just cleaning the room, the teacher said that she was computing her student's grades and the boy's classmate claims that he was listening to music.

Who committed the crime?