Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

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?

It is always ahead of me yet I can never see it. What is it?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

Three playing cards in a row. Can you name them with these clues? There is a two to the right of a king. A diamond will be found to the left of a spade. An ace is to the left of a heart. A heart is to the left of a spade. Now, identify all three cards.

Three friends named Mr. Black, Mr. Yellow and Mr. Green enter a pub on a weekend night. They are wearing either a Black, Yellow or Green shirt.

Mr. Yellow says to them, 'Did you notice that we all are wearing different color shirts than our names?'

To this, the man who was wearing the Green shirt said. 'Wow, thats right.'

Can you identify who is wearing which colour shirt ?

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?