Watch Where You Step
Why are manholes generally round, as opposed to square-shaped?
Three men order meals at $5 each for a total of $15. The waiter takes the check to the chef who, recognizing the patrons as his friends, asks the waiter to return $5.
Being dishonest, the waiter gives $1 to each of the men and pockets $2. Each of the men, essentially paid $4 for their meals but $4 x 3 plus the $2 pocketed equals $14. What happened to the other $1?
Wrong Bucket, but That's Okay
If you have a four and seven gallon bucket with no measuring marks, how would you measure out five gallons?
Chicken Crossed the River
A chicken, bag of feed, wolf, and you are on one side of a river. If the chicken is left with the bag of feed, it will eat it. If the wolf is left with with chicken, the wolf will eat the chicken. How do you get everyone to the other side if you can only take one entity with you at a time?
No Change too Little
You've inserted a coin into an empty bottle and closed it with a cork. How do you remove the coin without breaking the bottle or taking out the cork?
Two cubes are arranged on a secretary's desk such that they can be used to represent every day of the month. What number is on each face of the cubes to make this happen?
Who Hired the Electrician?
There are four switches in a hallway that can be turned on and off. One controls the light in the living room. The switch is off as are all of the others. You also don't know which switch controls the living room light. The other switches do nothing.
From the hallway, you can't see whether or not a light is going off in the living room.
Being able to flip switches as many times as you would like but only able to go into the room once before declaring which switch it was that turned on the light, how would you determine which switch controlled the living room light?
If you have a three and five unit measuring cup but you can't see the marks because you've used the cups so much, how do you measure out four units?
Dressing in the Dark
Twelve black socks and twelve white ones are in a drawer. Unable to see the socks, how many must be taken out to be sure that a pair matches?
Timed to Perfection
Two strings take exactly one hour to burn from either end. They burn at random rates though. How would you use the strings to measure 45 minutes?
Three boxes are in front of you. One says "Toys," another "Supplies," and the final, "Toys and Supplies." Knowing that each is labeled incorrectly, how do you label the boxes correctly if you can't look at the contents but can have someone pull an item out of one of them for you to see?