Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

What is so fragile that saying its name breaks it?

81 x 9 = 801. What must you do to make the this equation true?

What can you see in the middle of March and April that you can never see in any other month?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

Here is a conversation between a couple who both are software professionals.

Husband: Hey! What is your date of birth?
Wife Replied Angrily: It is 591062400
Husband after doing some calculations replied, "Got It".

What is the DOB of the wife?