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?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

What can you hold in your right hand, but never in your left hand?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

What number divided by 4 is the same as that number minus 4?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

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

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?