Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

There is a box in which distinct numbered balls have been kept. You have to pick two balls randomly from the lot.

If someone is offering you a 2 to 1 odds that the numbers will be relatively prime, for example
If the balls you picked had the numbers 6 and 13, you lose $1.
If the balls you picked had the numbers 5 and 25, you win $2.

Will you accept that bet?

How many times do a clock's hands overlap in a day ?

They are three errirs in this question. Can you find them?

Which fur should we be getting from the Lion?

Can you find a five letter word that is left with only two letters if one is removed?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

What number divided by 4 is the same as that number minus 4?

People put me on the table and cut me but do not eat me. What am I?

I welcome the day with a show of light, I stealthily came here in the night. I bathe the earthy stuff at dawn, But by noon, alas! I'm gone.