Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

There are hundred red gems and hundred blue gems. The blue gems are priceless while the red gems equal wastage. You have two sacks one labeled Heads and the other Tails. You have to distribute the gems as you want in the two sacks. Then a coin will be flipped and you will be asked to pick up a gem randomly from the corresponding sacks.

How will you distribute the gems between the sacks so that the odds of picking a Blue gem are maximum?

A Child was born in Lahore, Pakistan. Still, the child is not a Pakistani citizen. why?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Solve this tricky question. You are trapped in a forest. With you, you have a gun preloaded with two bullets in it. In front of you, there is a tiger, a leopard and a jaguar.

How do you survive?

Forwards I am heavy, backward I am not. What am I?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Can you solve the photo plexer logic ?

The horse jumps over the king.
Strangely there is absolutely no scratch on him.

Can anyone explain, how is this possible?