Your enemy challenges you to play Russian Roulette with a 6-cylinder pistol (meaning it has room for 6 bullets). He puts 2 bullets into the gun in consecutive slots, and leaves the next four slots blank. He spins the barrel and hands you the gun. You point the gun at yourself and pull the trigger. It doesn't go off. Your enemy tells you that you need to pull the trigger one more time, and that you can choose to either spin the barrel at random, or not, before pulling the trigger again. Spinning the barrel will position the barrel in a random position.
Assuming you'd like to live, should you spin the barrel or not before pulling the trigger again?
You are better off shooting again without spinning the barrel.
Given that the gun didn't fire the first time, it was pointing to one of the four empty slots. Because your enemy spun the cylinder randomly, it would have been pointing to any of these empty slots with equal probability. Three of these slots would not fire again after an additional trigger-pull, and one of them would. Thus, by not spinning the barrel, there is a 1/4 chance that pulling the trigger again would fire the gun.
Alternatively, if you spin the barrel, it will point to each of the 6 slots with equal probability. Because 2 of these 6 slots have bullets in them, there would be a 2/6 = 1/3 chance that the gun would fire after spinning the barrel.
Thus, you are better off not spinning the barrel.
Dave and Brad, two popular politicians, met at a club to discuss the overthrow of their party leader. They each ordered a vodka on the rocks. Brad downed his and ordered another. He then drank his second in a gulp and decided to wait before he ordered a third. Meanwhile, Dave, who was sipping his drink, suddenly fell forward dead. Both men were setup for an assassination. Why did Dave die and Brad live?
Both Dave and Brad were given drinks with poisoned ice cubes. Brad drank his drinks so quickly that the ice didn't have time to melt and release the poison.
A man is found hanging in a room 30 feet off the ground. There is nothing else in the room except for a large puddle of water on the ground. The police can't see any way the man could have climbed the walls to get to where he is hanging.
How did this man hang himself?
He stood on a tall block of ice and put the noose around his neck. Once the ice melted, he was hung, and all that was left was a puddle of water on the ground.
Two girls ate dinner together.
They both ordered iced tea.
One girl drank them very fast and had finished five in the time it took the other to drink just one.
The girl who drank one died while the other survived.
All of the drinks were poisoned.
How is that possible?
A man was shot to death while in his car. There were no powder marks on his clothing which indicated that the gunman was outside the car. However, all the windows were up and the doors locked. After a close inspection was made, the only bullet holes discovered were on the man's body. How was he murdered?