It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

What am I?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

Can you count the number of squares in the figure below?

A sundial has the fewest moving parts of any timepiece. Which has the most?

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?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?