What is so fragile that saying its name breaks it?

Can you fill the blank with the correct number?

6 30 870 756030 _____

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

I am a number I am not an odd number I am higher than 90 I am not higher than 100 If you subtract me from 100, you get nothing. What number am I?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

It has horns but can’t beep. It is like to bleat but It is not a sheep. What is it?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

What is the next number in this matchsticks series riddle?

Readers with the eyes of a hunter can find the snake in the field. Can you? Test your puzzle-solving skills now!