Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What has a ring but no finger?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

A new clothing store has a unique method of pricing items. A vest costs $20, a tie costs $15, a blouse costs $30, and underwear costs $45. How much would pants cost?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?