I always drive my customer away.

Who am I?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

A newspaper is supposed to have 60 pages, but pages 24 and 41 are missing.
Which other pages won't be there?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

81 x 9 = 801. What must you do to make the this equation true?

The more it dries, the wetter it becomes. Can you tell what it is?

Take one out and scratch my head, I am now black but once was red. What am I?