If eleven plus two equals one, what does nine plus five equal?

Find the missing letter in the last circle logically in the given below picture.

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

When 99 is considered higher than 100?

We are a group of eight brothers. We consider the weak, yet we protect the king in every battle. If we move ahead, we never turn back. Who are we?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

What is more useful when it is broken?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What 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?

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.