Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

What always comes into a house through the keyhole?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

Three people check into a hotel. They pay $60 for the rent of the room. After they check-in, the manager realize that the rent for the room is $55. So, he gives $5 to the bellboy and asks him to give it to them. The bellboy thinks that it will be difficult for the three people to share $5 among them and seeking the personal benefit, he pockets $2 and gives the remaining $3 to them.

Now, each person paid $20 and got back $1. In this manner, each of them paid just $19 which totals to the amount of $57. The bellboy has $2 with him and adding them, we get $59. So where is the remaining $1?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

There are forty elephants and they have forty-fore heads. How can this be possible?

If all the below statements are true

1. Gianni was either in Italy or France in 1997.
2. If Gianni did not kill Versace, Hilton must have killed him.
3. If Versace died of suffocation, then either Gianni killed him or Versace committed suicide.
4. If Gianni was in Italy in 1997, then Gianni did not kill Versace.
5. Versace died of suffocation, but he did not kill himself.

Who killed Versace and where was Gianni in 1997?

Different lights make me strange by changing me into different sizes. What am I?