Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

A mad serial killer kidnaps people and forces them to play the game of 2 pills with them, In this game, there are pills in the table and one of them is normal pill while the other one is deadly poisonous.
The victim will choose one pill and the killer will pick the other pill and both simultaneously will swallow the pill with water.
victim dies every time.

One day the serial killer kidnaps the Joseph and forces him to play the same game with him.

Joseph solves the mystery of the two pills and remains alive.

Explain?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

Can you find the odd number in the following?

2716, 4135, 5321 and 7145

If you paint a brown house white it will become a white house. If the stoplight changes from red to green, then the light is green. So, if you throw a white shirt into the Red Sea, what will it become?

If you go to the movies and you're paying, is it cheaper to take one friend to the movies twice, or two friends to the movies at the same time?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Complete the series by replacing "?" with the correct number.

ST ND RD TH '?'

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?