What is the fastest way to double your money?

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

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

What part of the chicken has the most feathers?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

I am first found in caves, now prolific online; I am a depiction, a drawing, a symbol, or sign. I will convey whichever mood you could wish; or for that matter, a fist, flask, or fish. What am I?

What 5-letter word typed in all capital letters can be read the same upside down?