How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

I am thinking of a five-digit number such that:
The first and last digits are the same, their submission is an even number and multiplication is an odd number and is equal to the fourth number. Subtract five from it and we obtain the second number. Then divide into exact halves and we get the 3rd number.

What number I am thinking of?

We are a group of eight brothers. We consider the weak, yet we protect the king in every battle. If we move ahead, we never turn back. Who are we?

A man was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?

What is the coolest letter in the alphabet?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

People make me, save me, change me, raise me. What am I?

I have branches, but no fruit, trunk or leaves. What am I?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?