What does this rebus means ?

PROG WORKRESS

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?

Buy me, smell me or deliver me, I do not change.

Who am I?

What jumps when it walks and sits when it stands?

Prove that twice of ten is the same as twice of eleven.

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?