Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

Two prisoners Jack and Jill are locked in a cell.
There is open window approx 40 feet above the ground of the cell.
They are never able to reach there.

Then they plan to escape by a tunnel and they start digging out.
After digging for more than 20 days, Jill comes with the different plan and they escaped.

what was the plan ?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Three people are in a room. Ronni looks at the Nile. The Nile looks at Senthil. Ronni is married but Senthil is not married. At any point, is a married person looking at an unmarried person? Yes, No or Cannot be determined.

Can you find out who is the kidnapper in below Picture and why, Explain ?

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.