Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

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?

What always comes into a house through the keyhole?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

A man has eighty-one cows ( numbered 1,2,3...81 as such). The beauty is that cow no. 1 gives 1ltr of milk, cow no. 2 gives 2ltrs of milk and so on. The man wants to equally distribute the cows among his nine sons so that each one of them gets the same quantity of milk.

You are given four tennis balls and asked to arrange those balls in a manner that the distance between each one of them is exactly equal. How will you do it?

'S' refers to the number of seconds in a day and 'H' refers to the number of hours in ten years. Which quantity out of these two is greater?

Why Aeroplane windows are round?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?