If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Write the next letter in this sequence.
O, T, T, F, F, S, S, E, __
**Hint: It is a Number Series Puzzle

How many triangles are there on the puzzle below?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

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

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.

In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

Can you fill the blank with the correct number?

6 30 870 756030 _____