What goes up but never comes down?

A man dies of old age on his 25 birthday. How is this possible?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

Nodes are shown below and you need to connect them based on the following rule: Every node can be connected to the number of nodes inside them, i.e. the first node there is a value of 1 which indicates that the first node can connect to exactly one node only.Can you do it?

While preparing the table for dinner, wife came up with an idea to tease his mathematician husband. She asked her husband to pick nine toothpicks and make ten without breaking any toothpick.

The husband was also smart and did it within seconds. How ?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

I’m tall when I’m young, and I’m short when I’m old. What am I?