If eleven plus two equals one, what does nine plus five equal?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

What can you catch but never throw?

What part of the chicken has the most feathers?

What can go up a chimney down, but can’t go down a chimney up?

What do you get if you add 2 to 100 four times?

I have a sore throat and a severe headache. I have four tablets with me that are identical to each other and they do not have any cover on them. There is no way I can identify which tablet serves what purpose. The only thing that I know is that two of these four tablets are for the throat and the remaining two are for the headache. To treat my condition, I must take 1 of each. What will I do now?

Can you spot the hidden girl in the picture below?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?