Replace the question mark with the number below given a simple math problem.

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?

There is a barrel with no lid and some wine in it. 'This barrel of wine is more than half full,' said Curly. 'No it's not,' says Mo. 'It's less than half full.' Without any measuring implements and without removing any wine from the barrel, how can they easily determine who is correct?

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

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

I have Rs.50 and I spend it in the way as below.

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?