By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

Look at the picture and find out which square is not linked with any of the other squares.

You along with your friend are standing in front of two houses. Each of those houses inhabits a family with two children.

Your friend tells you the below two facts:
1) On your left is a family that has a boy who likes accounts but the other child loves science.
2) On the right is a family with a seven-year-old boy and a newborn baby.

You ask him, "Does either of the family have a girl?"

To this, he replies, "I am not quite sure. But can you guess that? If you are right, I will give you $500."

Which family do you think is likely to have a girl?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

What has many teeth, but cannot bite?

What is both possible and impossible at the same time?

If it took eight men ten hours to build a wall, how long would it take four men to build it?