Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Why do we preferably have round manhole covers and not square ones?

Which English verb becomes past tense just by rearranging the letters?

Intelligence Agency need to break the vault but the problem is that they are not able to break the vault.

On the vault, a text is written as:

31 11 33 33 43 45
21 25
31 24 11 31 51 41

To Break the code Intelligence Agency brings a mathematician named Joseph.
Minutes later he deciphers the code.

Whats the code?

4 fathers, 2 grand-fathers and 4 sons went to watch the movie.What is the minimum number of tickets they need to buy ?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

What does this say?

XLR8

What does this rebus puzzle means ?