How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

What runs around the whole yard without moving?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

What is the centre of gravity?

Why is the longest human nose just 11 inches?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?