Can you fill the blank with the correct number?

6 30 870 756030 _____

What number comes next in the series?

5 15 5 18 5 24 14 20 _

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

In the four images below, can you find the odd one out?

In my garden, I have many trees but only one of them is the mango tree. In these mango trees, there are some mangoes(as expected).

But after a strong wind, there are neither mangoes on the tree nor on the ground. Explain?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

What is black when you buy it, red when you use it, and gray when you throw it away?