What word begins and ends with an E, but has only one letter?

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?

Why is it very easy to weigh a fish?

A sundial has the fewest moving parts of any timepiece. Which has the most?

I welcome the day with a show of light, I stealthily came here in the night. I bathe the earthy stuff at dawn, But by noon, alas! I'm gone.

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

What can you hold in your right hand, but never in your left hand?