using four eights (8) and a one (1) and one mathematical symbol , create the number 100

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

John had a bag containing colourful marbles. The colours are red, green and blue. The total number of marbles he had in his bag was 60. There are 4 times as many red marbles as green marbles. 6 more blue marbles than green marbles. How many marbles of each colour did John have?

What do you get if you add 2 to 100 four times?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

What does man love more than life, and hate more than death or mortal strife; that which satisfied men want; the poor have, and the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?