What has hands, but can’t clap?

A sea diver is a real show-off. He showed everyone that he can hold his breath underwater for 15 minutes.

I went to the diver and told him that I can be underwater for double the time i.e 30 minutes.
He responded that he will give me 100$ if I would be able to do it. I won 100$.

What did I do?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

Why is it very easy to weigh a fish?

What will you call your mother's brother's brother-in-law?

Why do we preferably have round manhole covers and not square ones?

In an Art Gallary, When the clock hit 11 am, Artist hung the painting number 30. When it struck 4 pm, he hung painting number 240 and when it struck 7:30 pm, he hung painting number 315.

Can you determine, which painting number will he hang when the time is 9:20 pm?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?