Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

What goes up but never comes down?

Considering the below equation:

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

Then, I + II + III = ?

Find the hidden tiger in the given optical illusion ?

What you cannot hold but it is yours?

How many times can you subtract the number 5 from 25?

I have Rs.50 and I spend it in the way as below.

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?