Why do people go to bed?

What Time Should the last watch show in the below figure?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

To attend world science seminar, A famous chemist from Mexico visit
London. In the lab, the scientist was killed and his six assistants were under suspicion of killing the chemist.
Name of six assistants: Austin, Wayne, Dege, Oscaru, Lingard, and Rojo.
He left a note "76-20-44 79-16-22-7"

A local detective Jack was called to solve the case,

After reading the note, Jack instantly asked the police to arrest the murderers.

Who are the murderers?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

O_er_t_o_

Complete the missing letters of the given word.

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

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?