Can you replace the question mark with the correct number in the below table sequence?

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

Which five letter word can be added at the end of below word to form a
valid word?

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I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

A man is shown a portrait painting. He looks closely, then tells, “Brothers and sisters have I none, but that man’s father is my father’s son!” Who is the man in the portrait?

Solve the following series:
AZ, GT, MN, __, YB

When it's bad luck to meet a black cat?

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 is full of holes but still holds water?