What goes up but never comes down?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

What is the next number in this matchsticks series riddle?

What is the Surname of Barbie Doll?

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

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?

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

The more of this there is, the less you see. What is it?