logicprobabilityYour 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.
cleanpoemsshortWhat has roots as nobody sees,
Is taller than trees,
Up, up it goes
And yet never grows?
A mountain.
cleanfunnyshortFour men were fishing in a boat on the lake. The boat turned over and all four men sank to the bottom of the lake. And yet, not one single man got wet. How is this possible?
All of the men were married.
cleanshortA boy was born in 1955. He just had his 18th birthday today. How did that happen?
1955 is not the year he was born. It was the hospital room he was born in
logicshortA teacher decides to give a pop quiz one day but all of her students refuse to take the quiz thinking that the teacher will call off the quiz. She can give only one of these students a detention for skipping the quiz. All of the students know each other’s names and if a student knows he/she is getting a detention they take the quiz.
How can she threaten her students with the single detention so they all take the quiz?
She tells them that she will give the student who skips the quiz whose name comes first alphabetically a detention. This student won’t skip because they know they are getting a detention if they do. The next person alphabetically will then know that they will get a detention so they won’t skip either, and so on.
cleanlogicshortwhat am II'm a fruit. If you take away my first letter, I'm a crime. If you take away my first two letters, I'm an animal. If you take away my first and last letters, I'm a form of music. What I am I?
Grape.
cleanfunnyloveshortWhat did the paper clip say to the magnet?
I find you very attractive.
logicmathprobabilityIn a supermarket, the first 25 customers of the day purchased an average of two items each.
After a further 15 customers, the average number of items purchased by each customer rose to eight.
What was the average number of items purchased by the last 15 customers only?
18
cleanshortWhat has four legs, but can't walk?
A table.
cleanfunnylogicloveA doctor and a bus driver are both in love with the same woman, an attractive girl named Sarah. The bus driver had to go on a long bustrip that would last a week. Before he left, he gave Sarah seven apples. Why?
An apple a day keeps the doctor away!
