An express train takes 3 seconds to enter the tunnel which is 1 km long. If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?
What is harder to catch the faster you run?
Can you find a number that lies one third of the distance between 1/3 and 2/3?
When it's bad luck to meet a black cat?
What can you serve, but never eat?
How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?
How many triangles are there on the puzzle below?
There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?
Can you arrange four 9's and use at most 2 math symbols, to make the total 100?
John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?
There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence. Do you know what word is that?
In the 1920s, people feared that crossword puzzles would contribute to illiteracy.