You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

Which tank will fill first?

When it's bad luck to meet a black cat?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

What number do you get when you multiply all of the numbers on a telephone's number pad?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

What begins with T, ends with T, and has T in it?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

Mr Black, Mr Gray, and Mr White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr Black, who hits his shot 1/3 of the time, gets to shoot first. Mr Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr Black, where should you shoot first for the highest chance of survival?