Can you replace the question mark with the correct number?

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

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

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

What two things can you never eat for breakfast?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?

A woman named Maria was at the funeral of her mother. She met a nice young man that she had never seen before and after the service, they spent a bit of time together. Then she got busy and didn’t get his name or phone number before he left. She tried to find him, but no one knew who he was or how to contact him. A few weeks later, Maria’s older sister dies and the police suspect murder. Who killed the sister?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

using four eights (8) and a one (1) and one mathematical symbol , create the number 100