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

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

What has many teeth, but cannot bite?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

What does below pictogram mean?

How far can you walk into the woods?