Logic riddles

logiccleansimple

A farmer is travelling with a fox, a sheep and a small sack of hay. He comes to a river with a small boat in it. The boat can only support the farmer and one other animal/item. If the farmer leaves the fox alone with the sheep, the fox will eat the sheep. And if the farmer leaves the sheep alone with the hay, the sheep will eat the hay. How can the farmer get all three as well as himself safely across the river?
The farmer takes the sheep across the river, then returns back. The farmer takes the fox across the river. The farmer takes the sheep back to the first side of the river. The farmer leaves the sheep back on the first side of the river, and takes the hay to the other side. The farmer returns to the first side of the river. The farmer brings the sheep back to the second side.
71.80 %
121 votes
logicsimpleclean

At a local bar, three friends, Mr. Green, Mr. Red and Mr. Blue, were having a drink. One man was wearing a red suit; one a green suit; and the other a blue suit. "Have you noticed," said the man in the blue suit, "that although our suits have colors corresponding to our names, not one of us is wearing a suit that matches our own names?" Mr. Red looked at the other two and said, "You're absolutely correct." What color suit is each man wearing?
Since none of the men are wearing the color of suit that corresponds to their names, and Mr. Red was replying to the man in the blue suit, it had to be Mr. Green to whom he replied. We then know that Mr. Green is wearing a blue suit. Therefore, Mr. Red is wearing a green suit and Mr. Blue is wearing a red suit.
71.80 %
76 votes
cleanlogic

A boy was rushed to the hospital emergency room. The ER doctor saw the boy and said, "I cannot operate on this boy. He is my son." But the doctor was not the boy's father. How could that be?
The doctor was his mom.
71.74 %
188 votes
logicsimpleclean

Without looking at a calendar, within a minute name a boys name using 5 consecutive first letters of 5 consecutive months.
JASON - July August September October November.
71.64 %
92 votes
logicsimpleclever

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.
71.56 %
67 votes
mathcleansimplelogic

Count the number of times the letter "F" appears in the following paragraph: FAY FRIED FIFTY POUNDS OF SALTED FISH AND THREE POUNDS OF DRY FENNEL FOR DINNER FOR FORTY MEMBERS OF HER FATHER'S FAMILY.
It appears 14 times. Make sure to count the "F"s in the word "OF", which people commonly miss.
71.53 %
50 votes
cleanlogicclever

You draw a line. Without touching it, how do you make the line longer?
You draw a shorter line next to it, and it becomes the longer line.
71.50 %
71 votes