The centre of the third figure is empty. What digit should fit inside?

What goes up but never comes down?

Which is the smallest number that you can write using all the vowels exactly once?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

What begins with T, ends with T, and has T in it?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

Where do fish keep their money?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?