How do you go from 98 to 720 using just one letter?

I make two people out of one. What am I?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

I know a nine-letter word having only one vowel.
Do you ?

If,

A + B = C
D - C = A
E - B = C

Based on the above equations, find out the answer for:

D + F = ?

A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

At a party, there are five people and a whole round cake lying at the centre of the table. Only four people will make a cut and take their piece and the last one will get the remaining piece on the table. How can they make sure that everyone gets a 1/5th of the piece?

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?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?