A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

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?

What is black when you buy it, red when you use it, and gray when you throw it away?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

What is the next number in the series?

15 29 56 108 208 ?

How many times can you subtract the number two from the number fifty?

When is the top of a mountain similar to a savings account?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?