What begins with T, ends with T, and has T in it?

What is the next number in this series?

4,12,84,3612....

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

To tease, King Akbar told his most clever advisor Birbal to give his daughter one thing that she can eat when hungry, drink if she feels thirsty and can burn if she feels cold. King Akbar was shocked when Birbal gave Akbar's daughter one such thing that satisfies all of the above.

What did Birbal give to Akbar's daughter?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

What will you call your mother's brother's brother-in-law?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

What have one eye but still cannot see?