Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Before Mount Everest was discovered, what was the highest mountain in the world?

There is an exact a week gap between Christmas and New Year. Hence, It is obvious that the new year that comes right after Christmas comes on the same day of the week.

A Strange thing happened in the Year 1777. Christmas occurs on Wednesday and New Year on Monday. How is that possible?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Can you guess the name of the month by looking the below rebus ?

If Japan and Panama decided to merge into a single country, probably people will name it Japanama.

Can you think of two more such country's unions that could produce similar names like Japanama by overlapping their three letters?

A man is trapped in a room. The room has only two possible exits doors. Through the first door there is a room constructed from magnifying glass. The blazing hot sun instantly fries anything or anyone that enters. Through the second door there is a fire-breathing dragon. How does the man escape?