You have 8 identical-looking coins. One of these coins is counterfeit and is known to be lighter than the others. You also have a two-pan balance scale. How can you identify the fake coin by using the scale only twice?

You must cut a birthday cake into eight equal pieces, but you’re only allowed to make three straight cuts, and you can’t move pieces of the cake as you cut. How can you do it?

This puzzle has been said to have been invented by Albert Einstein as a boy and some claim that only 2% of the population can solve it.

There are 5 houses in 5 different colors. All the 5 owners are of different nationality. The 5 owners drink different beverages, smoke different brand of cigars, and own different pets. No owners have the same pet, smoke the same brand of cigar, or drink the same beverage.

1. There are five houses.
2. The Brit lives in the red house.
3. The Spaniard owns the dog.
4. Coffee is drunk in the green house.
5. The Ukrainian drinks tea.
6. The green house is immediately to the right of the ivory house.
7. The Old Gold smoker owns snails.
8. Kools are smoked in the yellow house.
9. Milk is drunk in the middle house.
10. The Norwegian lives in the first house.
11. The man who smokes Chesterfields lives in the house next to the man with the fox.
12. Kools are smoked in the house next to the house where the horse is kept.
13. The Lucky Strike smoker drinks orange juice.
14. The Japanese smokes Parliaments.
15. The Norwegian lives next to the blue house.

Who owns the zebra?

A man goes into a barber shop and gets a haircut for \$15. He pays the barber with a \$20 bill, but the barber doesn’t have change. The barber goes to the neighboring flower shop and trades the \$20 bill for a \$10 dollar bill and two \$5 bills. Then he gives the man his \$5 in change.

Later the lady from the flower shop confronts the barber and tells him that the \$20 bill he gave her was counterfeit money. The barber agrees and he gives the lady a different \$20 bill.

Later that day he tries to figure out how much money he lost. How much money did the barber lose?

A man is trapped in a room with 2 doors and a small hole in the ceiling 10 inches in diameter. Behind one of the doors is an extremely hungry lion that hasn’t eaten in a couple of days. Behind the other door is a glass tunnel that magnifies the heat from the sun creating temperatures so high that even opening the door could kill you. How does the man escape?