No one wants to have it, but if one got it, he does not want to lose it. What is It?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

Decode the below four famous ciphers:

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

You walk into an old horror house. It has no power or plumbing. Once inside, you see three doors. Each door has a number on it. Behind each door is a way for you to die. Behind door number one, you die by getting eaten by a lion. Behind door number two, you die by getting murdered. Behind door number three, you die by an electric chair. You can’t turn back, so you have to go through a door. Which door do you go through?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

What does this mean?

CCCCCCC

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?