Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

Distances from you to certain cities are written below.

BERLIN 200 miles

PARIS 300 miles

ROME 400 milesAMSTERDAM 300 miles

CARDIFF ??? miles

How far should it be to Cardiff ?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

Why 1729 is a magic number? Answer Logically.

What four weights can be used to balance from 1 to 30 pounds?

Why do people go to bed?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I am an odd number. Take away a letter and I become even. What number am I?