What has no start, end, or centre?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?

John: "Hi Teacher, What is your favourite movie ?".
Chemistry Teacher: "Indium Cerium Platinum Iodine Oxygen Nitrogen".
Ten seconds later... John replied I got it.

Do you?

What question can you never answer yes to?

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

What number should come in place of the question mark below?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?