Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not-rounded numerals equals 24.

A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.” Who is in the painting?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

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?

Which country gets ill every time?

When we see 2 but call 10?

Can you decipher the two rows to find the hidden word?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

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

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?