Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

You can see it everyday, But cannot touch it at will. What is it?

You walk into a room and see a bed. On the bed, there are two dogs, five cats, a giraffe, six cows, and a goose. There are also three doves flying above the bed. How many legs are on the floor?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

What kind of band never plays music?

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

A man died and leaves Rs.10,000 in his will. There are 6 beneficiaries- his 3 sons and their wives. The 3 wives receive Rs.3960 of which Priyanka gets Rs.100 more than Tanu and Neha gets Rs.100 more than Priyanka.
Pramod gets twice as much as his wife, Tushar gets the same as his wife, and Prashant gets 50% more than his wife.

Who is married to whom?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

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.