How can you make number one disappear by adding something to it?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

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?

I am sure no one can have two things for dinner. what are they?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

A man has to get a fox, a chicken, and a sack of corn across a river.

He has a rowboat, and it can only carry him and one other thing.
If the fox and the chicken are left together, the fox will eat the chicken.
If the chicken and the corn are left together, the chicken will eat the corn.

How does the man do it?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?