Replace the question mark with the correct number in the below-given picture?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

The husband and wife were jogging in the morning. To match every two steps of the husband, the wife required three steps. If Both of them start with the here right foot. After how many steps do their left foot be together?

The richest man in the city Mr Rechard is kidnapped. James Bond is appointed to the case. At the crime scene, a note is found written by Mr Richard. The note read:

"First of January, Fourth of October, Fifth of March, Third of June."

James Bond knew that somehow, the killer's name was hidden in the note. The following were the suspects:

Jack Richard, the son and the heir of property.
John Jacobson, the employee of Richard.
June Richard, the wife of Richard.

James Bond took only a few moments to deduce the killer's name. Can you tell who was the killer?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?