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

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

What jumps when it walks and sits when it stands?

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

I make two people out of one. What am I?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Which is the correct shadow of the bird?

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?