Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What makes this number unique: 8,549,176,320?

Find the next number in the series.
1 10 24 43 67 ?

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

You can hear me, but you can't touch or see me.

What am I?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

In a chess board, the queen piece can move horizontally, vertically and diagonally freely. The picture represents the same.Can you place 8 queens on the board in a manner that none of the queens can attack each other?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

Solve below rebus puzzle?

I can write cow in 13 letters.

Can You?